Atlantic Canadian loggerhead turtle conservation action plan
Fisheries and Oceans Canada, Maritimes Region - October 2010
- Executive Summary
- Rationale for the Plan
- Species Description
- Population Status and Trends in Atlantic Canada
- Description and Analysis of Threats
- Fisheries Bycatch
- Fishery bycatch in Atlantic Canada
- Comparison of Canadian fishery bycatch with bycatch elsewhere in the North Atlantic
- Nesting Disturbance
- Additional Threats
- Conservation Efforts: Current and Future
List of Tables and Figures
Table 1. Average number of nests and mean of the log population growth rate for the Northwest Atlantic Recovery Units. Reproduced from Harris et al. (2010).
Figure 1. Distribution and magnitude of loggerhead turtle catches in the Canadian tuna and swordfish longline fisheries from 2000-2009 (yellow markers) and the Central North Atlantic Bluefin Tuna survey from 2001-2002 (green markers). Crosses indicate sets with zero loggerhead bycatch. The data are combined for all years and averaged by 10 nautical mile squares. The magnitude of markers represents the number of turtles caught per 1000 hooks. Purple line delimits the Canadian Exclusive Economic Zone. (Adapted from Paul et al. 2010) Elipses (red, dashed line) show approximate locations of concentrations of loggerhead sea turtles identified in MacAlpine et al. (2007).
Incidental capture of loggerhead sea turtles has been documented in the Canadian pelagic longline fishery.
Loggerhead sea turtles were assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) during their April 2010 meeting as endangered and are now being considered for listing under the species at Risk Act (SARA).
Academics, government and non-government organizations (International, American and Canadian) were invited to participate in the loggerhead sea turtle Recovery Potential Assessment (RPA) held February 15-17, 2010. Officials from the US National Oceanic and Atmospheric Administration (NOAA) also participated in the meeting as a continuation of the collaboration between Canada and the US on marine turtle conservation. All these groups are concerned about the conservation of loggerhead sea turtles and provided a consensus report documenting the known science, the level of incidental capture of loggerhead sea turtles by the Canadian pelagic offshore longline fleet and the potential impact on the recovery of the species. While it was observed that the pelagic longline fleet was found to be the major threat in Canadian waters, the range and scope of the threats overall would suggest that the Canadian fleet is not a primary threat to the recovery of the species. Reduction or elimination of mortality in Canadian waters alone is highly unlikely to be sufficient to achieve recovery. In addition to minimizing threats to loggerhead sea turtles in Canadian waters, international cooperation to reduce threats to the population as a whole is needed to achieve recovery of this species.
As part of continuing Canadian efforts to protect sea turtles the present document lays out the steps that need to be taken to move us toward our goal of improved knowledge and management of incidental catch in the Canadian Atlantic pelagic longline fisheries and summarizes the status of the loggerhead sea turtles in the Northwest Atlantic, the ongoing and planned Canadian efforts to monitor, conserve, and protect sea turtles, including identifying collaborative work with the US and international efforts aimed at more effectively coordinating, and jointly contributing to, the overall conservation and recovery of sea turtles.
Rationale for the Plan
The conservation status of loggerhead sea turtles (Caretta caretta) is of concern worldwide. The species was listed as Vulnerable on the International Union for Conservation of Nature (IUCN) Red List from 1982 to 1994, and was uplisted to Endangered in 1996 (IUCN 2009). As a member of the family Cheloniidae, loggerhead sea turtles are listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), which means that international trade of this species is prohibited (UNEP-WCMC 2010). In addition, they were listed as Threatened under the US Endangered Species Act in 1978 (National Marine Fisheries Service and US Fish and Wildlife Service 2008). In Canada, COSEWIC has assessed the status of the species (COSEWIC 2010a; b), and in response the government of Canada is considering listing loggerhead sea turtle the Species at Risk Act (SARA).
The Department of Fisheries and Oceans (DFO) convened a Recovery Potential Assessment (RPA) for loggerhead sea turtle in February 2010 in order to inform the listing decision. The purpose of an RPA is to undertake a scientific evaluation of the current status of the Designable Unit (DU), threats to its survival and recovery, and the feasibility of its recovery, and to provide consensus, science-based advice concerning these topics. Peer-reviewed science advice arising from the RPA is then available for consideration in SARA processes, including listing decisions and recovery planning. The RPA for loggerhead sea turtle brought together DFO science staff, external turtle experts from NOAA and academia, non-governmental organizations and industry representatives to review the best available information. Detailed advice and supporting documentation and analyses arising from the RPA are available elsewhere (DFO 2010; Harris et al. 2010; Paul et al. 2010).
The status of loggerhead sea turtle as a species of conservation concern and a decision on listing under SARA may take several years. In the interim period DFO is actively investigating strategies and tactics to reduce human impacts to loggerheads in the waters of Atlantic Canada. This Conservation Plan summarizes the status of loggerhead sea turtles in the Northwest Atlantic, and provides information concerning scientific investigations and fishery management efforts to mitigate harmful encounters in Atlantic Canadian fisheries.
DFO has long been involved in international recovery planning for loggerhead sea turtles and has more recently collaborated with US colleagues in the development of an action plan to consider implementation of shared approaches to by-catch data collection and mitigation of fisheries impacts in temperate waters. This Conservation Plan lays out the steps that need to be undertaken to advance toward the goal of improved knowledge and management of turtle interactions in Canadian Atlantic pelagic longline fisheries. These steps can be implemented under the Fisheries Act and through the Integrated Fisheries Management Plan (IFMP) as interim measures while the SARA process proceeds. Should the species be listed under SARA this Conservation Plan will form the basis of the recovery approach and subsequent action plan requirements under SARA.
The loggerhead sea turtle is one of six species of hard-shelled sea turtles that comprise the family Cheloniidae in the order Testudines in the class Reptilia. Atlantic and Pacific populations of the turtle are genetically distinguishable.
The loggerhead sea turtle has a relatively large head and beak. The head and carapace are generally reddish-brown, and plastron and other areas on its ventral surface are usually tan or yellow to creamy white in colour. Mature males can be distinguished from mature females by a longer tail and an enlarged curved claw on both of their forelimbs (Kamezaki 2003). The thick carapace of adult loggerheads has five vertebral scutes, usually five pairs of coastal scutes, 12 or 13 pairs of marginal scutes (including the supercaudal scute) and a wide nuchal scute that contacts the first coastal scute on either side (Kamezaki 2003).
Loggerhead sea turtles have both terrestrial and aquatic life stages, but most of their life is spent at sea. Mature females return to land to nest; males do not return to land. Loggerhead sea turtles forage for extended periods to accumulate reserves, and then migrate to their nesting grounds. Females reach sexual maturity around 30 years of age (range of 23 to 42 years) (National Marine Fisheries Service 2009). Females do not breed every year, and the interval between nesting seasons (remigration) is usually two or three years for individual turtles (National Marine Fisheries Service 2009). In the southeastern US, mating occurs from the end of March to early June, and nesting occurs between the end of April and early September (National Marine Fisheries Service and US Fish and Wildlife Service 2008). The eggs incubate for about two months (National Marine Fisheries Service and US Fish and Wildlife Service 2008). Hatchlings leave their natal beaches upon hatching. The rest of loggerhead sea turtle life history occurs in the ocean.
Loggerhead sea turtles utilize a variety of habitats as they progress through their life stages. They use three basic ecosystems: terrestrial – the nesting beach where egg laying, development and hatching occur, neritic – foraging in nearshore habitats where water depth is less than 200m, and oceanic – epipelagic (upper 200m of oceanic zone) foraging where water depths are greater than 200m (Bolten 2003).
The US Turtle Expert Working Group (Turtle Expert Working Group 2009) identifies five loggerhead turtle life stages, based on size (standard carapace length; SCL) and distribution:
- Year One, terrestrial to oceanic, size ≤ 15cm SCL
- Juvenile (1) exclusively oceanic, size range of 15-63cm SCL
- Juvenile (2), oceanic or neritic, size range of 41-82cm SCL
- Juvenile (3), oceanic or neritic, size range 63-100cm SCL
- Adult, neritic or oceanic, size ≥ 82cm SCL
The US Loggerhead Sea Turtle Biological Review Team recognizes nine loggerhead sea turtle distinct population segments (DPSs) globally as being biologically and ecologically significant (Conant et al. 2009). The Atlantic Canadian portion of the population is part of the Northwest Atlantic DPS, and most loggerhead sea turtles in Atlantic Canadian waters are likely oceanic juveniles (some may be neritic juveniles or adults) that originate from the nesting beaches of the Northwest Atlantic DPS (DFO 2010).
Loggerhead sea turtles occur the Atlantic, Pacific and Indian Oceans in both tropical and temperate waters. In the northwest Atlantic, the species is associated with the warm waters of the Gulf Stream off the edge of the continental shelf. In Atlantic Canadian waters during spring summer and autumn, loggerhead sea turtles range from Georges Bank, along the edge of the Scotian Shelf and Grand Banks to the limits of the Exclusive Economic Zone with occasional forays into waters on the shelf (Harris et al. 2010; McAlpine et al. 2007). The species exhibits a preference for warmer sea surface temperatures between 20-25°C and actively remain in these warmer water masses (Brazner and McMillan 2008; Watson et al. 2004). The rate of loggerhead sea turtle bycatch in Atlantic Canadian fisheries peaks in water temperatures between 24-25°C and then decreases rapidly (Brazner and McMillan 2008). The total number bycaught in US fisheries in the Northeast Distant fishing area (NED) peaked at 22°C (Gardner et al. 2008). There are few records of loggerhead sea turtles in coastal or inshore waters of Atlantic Canada despite considerable observer coverage in these areas (Figure 1), likely a result of water temperatures below the species’ minimum thermal tolerance. Their occurrence inshore may result from turtles remaining in warm-core rings of water, which break off from the Gulf Stream and move inshore (McAlpine et al. 2007).
Population Status and Trends in Atlantic Canada
There are currently no estimates of loggerhead sea turtle abundance in Atlantic Canadian waters. Data holdings concerning abundance and distribution in Atlantic Canada are limited to opportunistic sightings, fisheries bycatch, strandings and limited survey information. At present, the paucity of data precludes estimation of the abundance of the overall Northwest Atlantic population in the oceanic habitat (Harris et al. 2010; National Marine Fisheries Service and US Fish and Wildlife Service 2008). The best available information concerning population status is derived from nesting females. Abundance of nests can be used as an index of mature female abundance (Table 1). Estimates of the total number of nests on Northwest Atlantic nesting beaches have fluctuated between 47,000 and 90,000 nests per year over the last decade (National Marine Fisheries Service and US Fish and Wildlife Service 2008). Using minimum nest counts for 2004-2008, the median estimate for adult female population in the western North Atlantic is 30,050 individuals, with a minimum estimate of 16,847 and a maximum of 89,649 (National Marine Fisheries Service 2009).
Since females exhibit nesting site fidelity, trends in nests can be used as a proxy for trends in mature female abundance (Turtle Expert Working Group 2009). It is possible that these trends may not be reflected in the population segment located in Atlantic Canadian waters, or in the population overall. The nesting surveys are short time series and do not span even one generation (~46 years). Due to this long life history, there is a time lag between trends in nesting and those in the Canadian subpopulation. Despite these caveats, the trend in nest counts represent the best available index of abundance currently available. In general, there appears to have been a decline in the number of nests since 1989 in all of recovery units for which data are available, including the largest breeding unit in the Atlantic (Peninsular Florida) (Table 1; (National Marine Fisheries Service and US Fish and Wildlife Service 2008).
The US Atlantic loggerhead recovery team assessed the trends of the five recovery units, and the following paragraph is summarized from the US Recovery Plan (National Marine Fisheries Service and US Fish and Wildlife Service 2008). Trends in nest numbers from beach survey data for the Northern Recovery Unit, which encompasses over 80% of nests that may contribute to the population in Canadian waters, indicated a significant decline of 1.3% annually since 1983. Nest totals from aerial surveys indicated a 1.9% annual decline in nesting in South Carolina since 1980. Based on analyses of nesting beach survey data, the Peninsular Florida Recovery Unit (the largest recovery unit by far) has decreased by 26% from 1989-2008 and by 41% since 1998. The mean annual rate of decline for the 20-year period was 1.6%. Florida index nesting beach survey data for the Northern Gulf of Mexico Recovery Unit exhibited a significant declining trend of 4.7% annually. Data for the remaining two recovery units are limited. Nesting data from Quintana Roo, Yucatan, Mexico (Greater Caribbean Recovery Unit), indicated an increasing trend over a 15-year period from 1987-2001. However, nesting since 2001 has declined. Other smaller nesting populations within the recovery unit have exhibited declines over the past decades. The data time series in the Dry Tortugas Recovery Unit was insufficient to detect a trend (National Marine Fisheries Service and US Fish and Wildlife Service 2008).
Description and Analysis of Threats
Historically, there were substantial commercial and subsistence fisheries for loggerhead sea turtles in the Northwest Atlantic, as well as bycatch in other fisheries. Currently, most countries in the Northwest Atlantic prohibit harvest, except for 13 Caribbean countries or territories. The loggerhead harvest in the Caribbean is generally restricted to the non-nesting season, and most jurisdictions that allow harvest have regulations that favor harvest of large juveniles and adults, the most reproductively valuable stages of the population (National Marine Fisheries Service and US Fish and Wildlife Service 2008). Illegal harvest is considered to be an on-going threat (e.g.Koch et al. 2006), but harvest levels are largely undocumented.
Currently, the most important threats to loggerhead sea turtles can be grouped into two general categories: bycatch in fisheries and disturbance of nesting behaviour or nesting sites; with some additional, less important threats (Brazner and McMillan 2008; DFO 2010; National Marine Fisheries Service and US Fish and Wildlife Service 2008).
Bycatch of loggerhead sea turtles occurs in a number of fisheries throughout the species’ range in the Atlantic Ocean. The US Recovery Plan (Brazner and McMillan 2008; National Marine Fisheries Service and US Fish and Wildlife Service 2008) provides estimates of roughly 10,000-100,000 oceanic juvenile turtle and roughly 14,000-140,000 neritic juvenile turtle mortalities annually from all sources (primarily fisheries bycatch, but including vessel strikes, dredging activities, entanglement, and oil pollution) over the last decade. All pelagic longline fisheries prosecuted in the Atlantic Ocean were estimated to have caught between 150,000 and 200,000 loggerhead sea turtles in 2000 (Lewison et al. 2004). The vast majority of this effort is by countries other than Canada and the US.
Fishery Bycatch in Atlantic Canada
The only documented source of human-induced harm or mortality in Canadian waters is fishery bycatch in the Canadian pelagic longline fishery that targets swordfish and tuna species (Harris et al. 2010). It is considered likely that this bycatch comprises primarily oceanic and neritic juvenile turtles (DFO 2010). Estimates of total encounters with loggerhead sea turtles in this fishery were provided by Paul et al. (2010). In summary, bycatch in this fishery was estimated using observer data, and bycatch rates from observed trips were then extrapolated to the entire fishery using a ratio estimation method (see below). Paul et al. (2010) estimated that approximately 1,200 loggerhead sea turtles (95% confidence range of 700-1,800) were caught annually in Canadian tuna and swordfish longline fisheries during the period of 2002-2008.
Under the assumption that post-hooking mortality ranges between 20-45% of bycaught individuals (Chaloupka et al. 2004; Parker et al. 2005; Sasso and Epperly 2007), approximately 200-500 mortalities of oceanic/neritic juveniles occurred annually (2002-2008) in this fishery.
Comparison of Canadian Fishery Bycatch with Bycatch Elsewhere in the North Atlantic
Most of the available information concerning loggerhead sea turtle bycatch in fisheries in the North Atlantic, exterior to Canadian jurisdiction is derived from US commercial fisheries. The information summarized here was based on estimates collated in the US Recovery Plan for the Northwest Atlantic Population of the Loggerhead Sea Turtle (National Marine Fisheries Service and US Fish and Wildlife Service 2008; see the Plan for details on how these bycatch estimates were derived). As in Canada, international pelagic longline fisheries encounter loggerhead sea turtles. The US Recovery Plan provides a (logarithmic midpoint) total bycatch estimate of 30,000 loggerhead sea turtles encountered annually in the North Atlantic. In addition, bycatch has been identified in a number of other international trawl, gillnet and dredge fisheries that target approximately 15 different species. For example, the various US shark fisheries and the eastern scallop dredge fisheries each account for roughly 1,000 bycaught loggerhead sea turtles annually, and total bycatch in all trawl fisheries has been estimated (logarithmic midpoint) at 30,000 individuals annually (Brazner and McMillan 2008; National Marine Fisheries Service and US Fish and Wildlife Service 2008).
The US Recovery Plan provides mortality estimates in units of “adult equivalencies”, wherein mortalities at each life stage are adjusted for expected lifetime reproductive contribution, given the individual’s age, probability of reaching maturity and expected life span (Table A1-4 in National Marine Fisheries Service and US Fish and Wildlife Service 2008). This conversion takes into account the relatively high age at maturity exhibited by loggerhead sea turtles, and that individual turtles are likely to die before achieving maturity and producing offspring (i.e. deaths occurring at younger ages do not have the equivalent impact of mortalities to adult, breeding females). Conversion of the life stages caught in the Canadian tuna and swordfish longline fisheries (oceanic and neritic juveniles) to adult equivalents using survivorship rates provided in the US Recovery Plan results in an estimate of 5-15 adult equivalent mortalities annually for 2002-2008. For comparison, estimates of total annual mortalities in adult equivalents for the North Atlantic overall are 9,417 individuals for trawl fisheries and 872 individuals for pelagic longline fisheries.
Paul et al. (2010) provided a comparison of loggerhead sea turtle bycatch rates in the US and Canadian pelagic longline fisheries prosecuted in and adjacent to Atlantic Canadian waters. Given that the US fishery largely targets swordfish, while the Canadian fishery targets either swordfish or tunas, Paul et al. (2010) disaggregated Canadian data into the two target groups to allow for further comparison. Paul et al. (2010) determined that targeting of tunas in the Canadian pelagic longline fishery was an important correlate of encounter rates of loggerhead sea turtles, with higher encounter rates observed when the fleet targeted tunas. When swordfish were targeted, encounter rates over the 2005 through 2007 period were comparable to published reports for the US pelagic longline fishery (Fairfield-Walsh and Garrison 2006; Fairfield-Walsh and Garrison 2007; Fairfield-Walsh and Garrison 2008; Paul et al. 2010). Bycatch rates in the Canadian swordfish-directed sets were similar to those in the swordfish fishery conducted in adjacent waters, whereas bycatch rates were higher when the Canadian fishery targeted tropical tunas.
Estimates of loggerhead sea turtle encounters in the Canadian tuna and swordfish were calculated using a ratio estimation method (Paul et al. 2010). Bycatch rates were then extrapolated to the entire fishery (DFO 2010). Loggerhead sea turtle bycatch in US pelagic longline fisheries has been estimated using a delta-lognormal statistical model, with similar extrapolation to the entire fishery (e.g. Garrison et al. 2009). Paul et al. (2010) also used this delta-lognormal approach for comparison with the ratio estimation method and for easier comparison with the US methodology. A delta-lognormal model with region and fishing quarter as stratifying variables predicted almost 50% fewer loggerhead sea turtle encounters in the Canadian pelagic longline fishery than applying the ratio estimation model within the same strata, but trends both within and across years indicated by both approaches were quite similar. Paul et al. (2010) attributed the lower encounter rate from the delta-lognormal method to the model using only that portion of the total fleet that typically encounters turtles (sets without turtle bycatch are not used in the pro-ration of catches). Peer review during the DFO loggerhead sea turtle RPA led to the selection of the ratio estimation method over the delta-lognormal approach, as the delta-lognormal model was considered too restrictive in the inclusion of sets in estimation of bycatch rate (DFO 2010).
As stated previously, loggerhead sea turtles do not nest in Canada. This broad category includes human activities that either directly disturb a nest (causing mortality at the egg stage), or prevents a female from coming ashore and nesting successfully. A variety of specific human activities fall into this group, including: beach cleaning, human presence on nesting beaches at night, recreational beach equipment, driving on nesting beaches, beach sand placement, beach armouring, sand fences, and shoreline stabilization activities in the vicinity of nesting beaches. See the US Recovery Plan for the Northwest Atlantic Population of the Loggerhead Sea Turtle for more information (National Marine Fisheries Service and US Fish and Wildlife Service 2008).
Ship-strikes, illegal harvest, pollution in the form of entanglement in marine debris, offshore oil and gas production, climate change and trophic changes have been identified as potential threats to oceanic loggerhead sea turtles (Conant et al. 2009; COSEWIC 2010b; Harris et al. 2010). There are no documented cases of these threats causing harm or mortality in Atlantic Canadian waters, but this may be a reflection of the lack of information rather than that no harm has occurred. In some areas beyond Canadian waters, propeller and collision injuries from boats and ships are common in sea turtles. From 1997 to 2005, approximately 15% of all stranded loggerhead sea turtles in the US Atlantic and Gulf of Mexico were documented as having sustained some type of propeller or collision injuries although it is not known what proportion of these injuries were post or ante-mortem (National Marine Fisheries Service and US Fish and Wildlife Service 2008). In the US, killing of nesting loggerhead sea turtles is infrequent. In some other jurisdictions, illegal take of sea turtles is considered a substantial threat, although mortality estimates are unavailable (National Marine Fisheries Service and US Fish and Wildlife Service 2008).
Conservation Efforts: Current and Future
Background and History
In 2001 and 2002, the Nova Scotia Swordfishermen’s Association (NSSA) obtained funding through Environment Canada’s Habitat Stewardship Fund to pay for increased observer coverage to determine the extent and possible means for mitigation of sea turtle by-catch by their fleet. In 2003, the NSSA developed a Code of Conduct for Responsible Sea Turtle Handling and Mitigative Measures, which was added to the fleet’s Conservation Harvesting Plan in 2004. This voluntary Code of Conduct is attached to fleet licence conditions. Included are measures such as avoiding areas of high sea turtle capture rates, notifying all vessels operating in the area if high sea turtle capture rates are encountered, gear hauling protocols to minimize harm to any turtles that may be captured, and sea turtle handling guidelines and usage instructions for de-hooking gear. Over the course of 2003-2004, de-hooking and line-cutting kits were purchased by the NSSA to supply each active vessel in the fishery. In 2008, representatives from all vessels currently active in this fishery received training and certification in the use of this equipment through a workshop given by the US National Marine Fisheries Service. The majority (90%) of the fleet now uses circle hooks to increase the chances of survival for some discarded species. Also, the typical gear configuration allows sea turtles to get to the surface to breathe, which enables live release in nearly all cases.
Other measures currently in place include mandatory release of loggerhead sea turtles, tracking of vessels via Vessel Monitoring System (VMS), 5% observer coverage of fishing trips, and an additional 5% in 2009/10 and 2010/2011 to better determine the level of precision of encounter estimates and to improve spatial coverage.
The DFO RPA for loggerhead sea turtle documented the level of incidental capture of loggerhead sea turtles by the Canadian pelagic offshore longline fleet and the potential impact of these encounters on the recovery of the species. The RPA was unable to assess the impact of proposed mitigation strategies on population abundance and distribution in Canadian waters, however the range and scope of the threats overall would suggest that the Canadian fleet is not the primary threat to the recovery of the species. In addition, an on-going, multiyear project undertaken by DFO to evaluate bycatch in most of the fisheries in the Maritimes Region provides little evidence for additional interactions with loggerhead sea turtles in other fisheries. Nonetheless it was recognized during the RPA that Canadian mitigation measures can contribute to population recovery, although it is very likely that the measures on their own would have little impact to the recovery of the species; international cooperation to reduce threats to the population as a whole is needed to achieve recovery (DFO 2010). Below is a list of initiatives proposed to mitigate future loggerhead sea turtle encounters in the Canadian pelagic longline fishery in the short- and medium-term.
Strategies and Actions for Bycatch Mitigation (Pelagic Longline)
The only documented source of human-induced harm or mortality to loggerhead sea turtle in Canadian waters is the tuna and swordfish pelagic longline fishery. It should be recognized that mitigative actions in Canadian fisheries alone may not result in substantive changes in loggerhead productivity, and hence abundance. Nonetheless, it is necessary to explore the extent to which more can be done to modify or restrict human activities that would prevent further deterioration, or even allow for some improvement, in stock status. The route to effective action is to enlist both international cooperation and the fishermen involved in these fisheries to minimize loggerhead interactions. This is what is proposed below.
“Ensure that human-induced harm in Canadian waters does not exceed levels that would impede population recovery and encourage increases in abundance toward what might be considered to be historical levels, through implementation of practical solutions, with industry cooperation, for monitoring and mitigating incidental capture and post-release mortality of sea turtles by Canadian commercial fleets”.
1. Enhance monitoring and data collection for loggerhead turtles
Actions underway 2010/11:
1.1. Maintain and/or increase observer coverage to ensure statistically robust estimation of bycatch levels.
1.2. Share best practices from others (e.g. USA) and adopt or develop protocols for boarding sea turtles to further improve disentanglement and de-hooking, and thus enhance post-capture survival.
1.3. Use the Maritimes Region bycatch project as a means to conduct enhanced industry outreach.
1.4. Review the Observer contract requirements and identify necessary amendments or additions to institute improved data collection requirements.
1.5. Review logbook data collection for potential improvements.
1.6. Provide data on incidental catch of sea turtles to ICCAT as requested in ICCAT circular 413/10.
Actions planned for 2011/12:
1.7. Work with the Canadian Pelagic Longline fishery and Observer program staff to transfer and implement practices for handling and boarding of sea turtles.
1.8. Obtain data on life-stage of loggerhead sea turtles foraging in Canadian waters. Boarding turtles will provide access to the bycaught animals and enable accurate measurements of individuals, along with other research opportunities.
2. Continued International Cooperation and Capacity Building
2.1. Review methodologies currently in place to estimate loggerhead sea turtle encounters with a view of harmonization with the US. Currently Canadian statistical methodology (ratio approach) results in higher estimates.
2.2. Bilateral work with US (best practices for mitigation of sea turtle bycatch and safe handling and release).
2.3. Participation in the Kobe bycatch workshop on improving cooperation and coordination among RFMO’s.
Actions long term:
2.4. Coordination with other parties to support the adoption of consistent sea turtle conservation and management measures within all RFMO’s.
2.5. Continued participation as an observer in the inter-American Convention for the protection and Conservation of turtles (IAC).
2.6. Possible development of catch reduction proposals pending the outcome of the Kobe Bycatch workshop and associated recommendations.
3. Introduce fishery management measures to mitigate bycatch
3.1. Develop more stringent protocols related to implementation of the Code of Conduct beyond those currently in use.
3.2. Move to mandatory use of corrodible 16/0 circle hooks by December 2011 to reduce mortality of released loggerhead sea turtles.
3.3. Require the mandatory use of safe handling and release equipment and protocols beyond those currently in the voluntary code of conduct by May 2011.
3.4. Assess feasibility and potential effectiveness dynamic/temporary, time/area, temperature-based closures to minimize loggerhead sea turtle interactions.
3.5. Possible changes to gear configuration and fishing practices based on results of research.
4. Research in support of Strategies
4.1. Determine if stable spatial/temporal hotspots for loggerhead sea turtle bycatch exist in Canadian waters.
4.2. Investigate effects of gear deployment (e.g. set time, set duration) on the frequency of encounters.
4.3. Activities identified in the DFO Maritimes sea turtle research plan:
4.3.1. Analysis of data from enhanced Observer coverage undertaken in 2001 and 2002 to improve monitoring, if improvements are required.
4.3.2. Documentation of current fishing practices and literature review.
4.4. Use improved data collection identified in the Monitoring section above to enhance estimation of post-release mortality of bycaught turtles.
4.5. Keep abreast of international studies investigating post-release survival of bycaught loggerhead sea turtles.
4.6. Develop spatial/temporal models of loggerhead sea turtle habitat in Canadian waters, and compare habitat location(s) to sea surface temperature and spatial distribution of the Canadian pelagic longline fishery.
The various measures presented above are anticipated to lead to a reduction in loggerhead sea turtle encounters in pelagic longline fisheries. As an example NOAA Fisheries has estimated both the anticipated reduction in bycatch that would result from US longline fleets switching from J to circle hooks, and increased post release survival when all gear is removed from bycaught individuals (e.g. National Marine Fisheries Service 2004), as is required under the measures presented above.
Items identified in this Conservation Plan constitute current Canadian efforts to protect loggerhead sea turtles. The Plan will be updated in the future as new knowledge leads to improved assessment of population status in the Northwest Atlantic and identification of potentially effective measures for management of incidental catch in Atlantic Canadian fisheries. Canadian efforts to monitor, conserve, and protect sea turtles will continue; this includes identification of collaborative work with the US and international efforts aimed at effective coordination and joint contribution to the overall conservation and recovery of sea turtles. The highly migratory behaviour of the loggerhead sea turtle necessitates that responsibility for conservation of this species is shared among many countries. Given the broad scope of the threats outside of Canadian waters the conservation efforts presented in this Plan, while not sufficient to ensure the recovery of the species, demonstrates Canada's commitment to assist the international community in their recovery efforts.
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Table 1. Average number of nests and mean of the log population growth rate for the Northwest Atlantic Recovery Units. Reproduced from Harris et al. (2010).
|Northwest Atlantic Recovery Units||Years of data (nests)1||Average number of nests1||Years of data
|Arithmetic mean of
the log population growthrate [95% C.I.]2
|Northern||1989-2008||5,215||1983-2005||-0.012 [-0.079, 0.055]|
|Peninsular Florida||1989-2007||64,513||1989-2007||-0.026 [-0.065, 0.013]|
|Northern Gulf of Mexico (Florida
|1995-2007||906||1997-2007||-0.049 [-0.121, 0.022]|
|Greater Caribbean||1989-20053||1,6743||1989-2006||-0.012 [-0.068, 0.043]|
1 (National Marine Fisheries Service 2009)
2 (Conant et al. 2009)
3 (Turtle Expert Working Group 2009)
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