Sharks

The Save Our Sharks team is looking back at a very successful year and a half of campaigning for shark conservation. Since kicking of in June 2015, we organized a myriad of activities and events reaching a continuously growing audience in the Netherlands and the Caribbean. There were press trips, radio and television interviews, tagging trips, and plenty of activities mixing fun with education. And all the while we accomplished both giant strides and small steps towards the level of protection that sharks so desperately need.

We hereby proudly present an overview of what we have accomplished so far, highlighting the great work by everyone involved in the project. Work that is made possible by the generous financial aid of the National Postcode Lottery, to whom we owe a debt of gratitude.

Tadzio Bervoets, Save Our Sharks project leader 

The Dutch Caribbean is poised to benefit from a new funding initiative provided by the Dutch Postcode Lottery aimed at an essential conservation effort – protecting our sharks. The fund will provide €1.6 million to assist with shark conservation on all six islands of the Dutch Caribbean; Saba, St. Eustatius, St. Maarten, Curaçao, Aruba and Bonaire. “Save our Sharks” is one of only five major shark conservation projects running globally.

This news article was published in BioNews 17.

BioNews is produced by the Dutch Caribbean Nature Alliance and funded by the Ministry of Economic Affairs.

The occurrence of basking sharks in the Caribbean Sea is only recently documented by satellite tagging studies, which show that some individuals migrate through the region en route from waters off the east coast of the USA to waters off northeastern South-America. The observation of a basking shark on 7 November 2013 ca. 130 km north-northeast of Aruba during an aerial survey of marine mammals in the waters around the Dutch Leeward Islands is reported. This observation constitutes the rst visual record of a living basking shark in the Caribbean. 

The populations of sharks worldwide are in sharp decline and therefore in urgent need of protection from illegal fishing and fisheries by-catch.The establishment of this Sanctuary for sharks, as well as marine mammals, was at the request of the Governments of Bonaire, Saba and St Eustatius.The local nature conservation and fisheries organizations are involved in the protection. The name of the Sanctuary “Yarari” is a Taíno Indian word, meaning ‘a fine place’.

Yarari sanctuary GIS data can be found at:

• Bonaire: Exclusive Economic Zone
• Saba and St.Eustatius: Exclusive Economic Zone

Findings on Marine Turtles
·         Migration routes to and from nesting sites (typically index beaches) are variously known in the Caribbean, increasingly from satellite telemetry and studies of genetics. Without doubt the WWF priority areas are connected to each other, as well as to others in the Caribbean and to the high seas, especially the Sargasso Sea, through their shared responsibility for marine turtles during their different life stages.
·         Nesting habitat for marine turtles in the Caribbean are reasonably well know, although data is continually accruing from existing and new projects that monitor nesting activity. The imperative is to capture and share data in a meaningful way so as to enable comparison between sites and to permit the analysis of population trends.
·         There is a growing focus on in-water monitoring which helps to shed light on foraging sites. A number of parallel efforts by coral reef researchers to monitor ecosystems also provide valuable information on coral reef health and resilience to climate change in the region. While these studies are useful in highlighting overall declines in the coral reef ecosystems upon which marine turtles depend, there was found to be lack of similar efforts to monitor seagrass habitat for marine turtles, or  water  quality  monitoring  in  what  is  a  highly  populated  region  with  increasing  coastal development that generally lacks urban environmental infrastructure.
·         MPAs in the Caribbean have not specifically been designed as a network to protect endangered marine turtles in their different life stages and habitats. There is better coverage of nesting beaches via terrestrial protected areas than of foraging sites in marine protected areas (MPAs), which also reflects the reality of competing interests from fisheries, oil exploration and infrastructure development. Effective MPAs require adequate management capacity, and enhanced enforcement capacity is a top priority need among Caribbean MPAs.
·         Threats to marine turtles are extensive. The most common threats to nesting turtles shared by the priority areas are artificial lighting, beach erosion/accretion and pollution The most common threats to foraging/migrating turtles are fisheries entanglement, bycatch and pollution. Throughout the Caribbean it is evident that financial and human resources are a major challenge for governments, NGOs and communities in taking forward marine turtle conservation efforts.
 
Findings on Sharks
·         Information relevant to sharks in the Caribbean was found to be spread throughout a wide range and a large volume of literature. The disparate sources of shark information include reports from national scientific and fisheries divisions, from regional fisheries management organizations, from multilateral  agencies,  and  from  regional  and  international  academic  institutions.   Only  one publication was found to bring together regional shark information.
·         Consultation with key shark experts indicated that much is still unknown about sharks, even for the more common shallow water species. Still less is known about pelagic sharks and their movements into and through the eco-regions of the Caribbean.
·         Information on sharks was found to be unevenly distributed amongst the priority areas covered in this inventory. More extensive information on sharks was found to exist for non-priority areas of the Caribbean, such as Venezuela and the US, than for the priority areas. The inventory serves to highlight geographical gaps in knowledge about sharks in the Caribbean, for example in relation to Cuban sharks, and these geographical could guide further investigation.
·         Insufficient data exists to determine which shark species are of possible concern in the Caribbean. Also complicating the Indices of relative abundance were found to sometimes provide conflicting information on population trends.
·         Although sharks are highly migratory, information on shark movements in the Caribbean and the Sargasso Sea comes from only a handful of sources.
·         Some landings data exists for shark fisheries and some data exists on the incidental capture of sharks in other fisheries. However, making meaningful comparisons between datasets is a complex and time-consuming task which could be undertaken with a specialist partner such as a regional fisheries management organization or a researcher.
·         There is scope to seek further input on sharks from a number of knowledgeable experts who were willing to contribute but were unavailable for consultation in the timeframe of this inventory.
·         Some of the information that was compiled in the course of the inventory was found to be old and/or limited in its coverage. Expert consultation raised a number of doubts about key references such as IUCN classification of sharks. There is a fundamental need to validate the presence of sharks in the region and assess their population status. Recommended follow-up to this inventory could be key local informant interviews with fishers and relevant local experts in each of the priority areas about shark sightings, catch and bycatch.
·         A key step towards effective management of Caribbean Sharks would be a meeting of regional shark scientists and experts to share data, assess its application to conservation and sustainable use, and to develop a strategy for addressing significant gaps in knowledge. Such a meeting focused on Caribbean sharks has not yet been achieved.
 
Recommendations on GIS
·         Continue GIS data scoping and the collection of existing information from organisations working on similar initiatives. Invest in understanding existing governance frameworks and building partnerships for future collaboration with other regional fisheries management organisations, BINGOs (TNC and ICUN),  Universities  (UWI,  CERMES),  local  and  regional  NGOs  (see  Mahon  et  al.  2013  for  full Caribbean governance review), with a view to developing a data sharing agreement with key partners. This would enable continued sharing of GIS data collected and produced with others practitioners working the region.
·         Construct a Geodatabase that addresses WWF’s strategic priorities in the Caribbean region and which fills gaps in existing GIS information for these priorities. This could provide a valuable spatial synthesis of several types of information relevant to the priority areas.
·         The largest GIS data gap is in relation to sharks. There are a number of studies on sharks (i.e. NOAA fisheries observer boats, Fisheries Division’s datasets) but this data needs to be compiled and GIS data produced, which requires more significant effort than was possible within the scope of this inventory.
·         There are also opportunities to improve GIS data related to marine turtles. Turtle migration is an example of this. There are multiple initiatives by various different turtle conservation organisations and academic institutions that are tracking the migrations of marine turtles in the region, especially by satellite.  GIS data from satellite tracking from various locations in the region exists, but it has never been compiled at the regional level for large scale analysis of marine turtle migration. This task could be usefully undertaken in future, ideally in conjunction with the WIDECAST network.
·         We note that some marine turtle data used in GIS are dynamic rather than static in nature and in the interests of data integrity they would benefit from updating. For example, new information is constantly becoming available from nesting monitoring activities, both new from new projects and the ongoing activities of longer term projects. There have also been discoveries of marine turtle aggregations at foraging sites, providing new data to input to GIS. Threats to marine turtles across the region are emerging and changing, for example in relation to tourism development, and creative approaches to GIS representation of this information could be developed to assist with monitoring impacts on population status and trends.
·         In  the  course  of  this  inventory  we  explored  some  new  approaches  to  mapping  marine  turtle populations   and   trends   with   the   aim   of   assisting   interpretation   and   enhancing   strategy development. The sample maps are based on data from Bonaire and the Guianas only, since comparable datasets were either missing for the other priority areas or could not be provided in the timeframe of the inventory.  There is potential to work further with WWF on the development of new GIS layers that directly feed into the strategy development process.
 

Worldwide many shark populations are in strong decline mainly due to fisheries. Population status of sharks in the Caribbean is still poorly known. In order to be able to take effective measures to protect sharks, insight in their spatial behaviour during different life stages is required. Do marine parks enhance shark populations and if so at what scale?
In the Caribbean Netherlands, a unique opportunity for research on spatial behaviour is provided by the still relative high abundance of sharks on the Saba Bank, Saba and St Eustatius. To study individual movement patterns and site fidelity of sharks species that use reefs, acoustic telemetry is a proven successful technology.
As a first step, we started a pilot study with acoustic telemetry on Caribbean reef sharks and nurse sharks on the reefs directly around Saba in October 2014. Our goals were to obtain: 1) experience with using existing infrastructure and organisations in setting up a shark telemetric study; 2) experience in catching methods and insight in effort needed for these target shark species; 3) a first indication of the scale of individual movement patterns in time; and 4) raise local awareness of importance of sharks.
An array of eight detection stations (VEMCO VR2W receivers) was deployed on or near existing anchored mooring buoys at the pinnacles and the reef surrounding the island of Saba. In the last week of October 2014, in total eight Caribbean reef sharks (115-184 cm) and four nurse sharks (94-210 cm) of different life stages were implanted with VEMCO V16 transmitters (with battery life of 4.5 years) and released at the catch site. For Caribbean reef sharks, rod and line, and for nurse sharks, long-line fishing for short duration during night proved most favourable, though catching nurse sharks required more effort than Caribbean reef sharks. In addition, two nurse sharks were obtained from bycatch in lobster pot fisheries.
A first read out of the receivers was carried out in early December 2014. The first preliminary results showed that all sharks were detected after release and that most Caribbean reef sharks were detected throughout the first six weeks and mostly around only a few receivers. This suggests a very local habitat use of the reefs around Saba. Two Caribbean reef sharks appear to use a larger proportion of the reefs around the island. For the three juvenile nurse sharks habitat use appeared to be even more local since they were only detected at one receiver throughout the first six weeks. The larger female nurse shark was only detected directly after release and her spatial behaviour thereafter remains unclear as of yet.
In the coming years these sharks will yield more data on year-round habitat use. In the autumn of 2015 we will also use a mobile receiver to detect tagged sharks present at the reefs around Saba in between the stationary receivers. Furthermore, to answer research questions about dispersal, migration, connectivity and meta-population structure we aim to expand the telemetry study to the Saba Bank and given sufficient budget also surrounding islands of St. Eustatius and St. Maarten in 2015.
This pilot study could only be performed through the support of many people and organisations, e.g. the Saba Conservation Foundation. The shark research of IMARES and partners was presented at Sea & learn in Saba and the fieldwork was documented for two Dutch Caribbean TV-programmes. WWF, Wereld Natuur Fonds the Netherlands (WNF), and the Dutch Ministry of Economic Affairs provided the funding for this study.

Many environmental variables may influence fish assemblage structures in terms of abundance, biomass and mean size. The aim of this study is to provide a baseline survey on reef fish assemblages and shark presence covering the whole Saba bank (Dutch Caribbean). Hereby determining the influence of habitat, depth and fishing pressure on the structure of reef fish assemblages and shark presence. Baited Remote Underwater Video (BRUV) survey was used to describe reef fish assemblage structures on the Saba bank. Between 2012-2014, a total of 165 60 min BRUV deployments were conducted on locations varying in habitat complexity (0-4, Polunin and Roberts, 1993), depth (15-40m) and fisheries. The eleven most abundant fish species observed on the Saba bank represented eight families and accounted for nearly 50% of the total number of individual fish observed. Labridae was the most abundant fish family observed with a relative abundance of 22%. Most abundant fish species by number of individuals were Thalassoma bifasciatum (N=849 (9.8%)) Stegastus partitus (N=725 (8.4%)) and Acanthurus bahianus (N=430 (5.0%)).

Habitat complexity was positively correlated with species richness (Nsp), fish abundance (MaxN), and mean biomass, and negatively correlated with mean fish length. Strongly developed vertical relief habitats were found to support high numbers of fish species (N=19.1±0.6SE) of relatively low mean lengths (22.4cm±0.3SE), whereas less complex habitats were characterized by low numbers of species (N=8.3±0.8SE) with relatively high mean lengths (24.6cm ±0.81SE). Depth was negatively correlated with Nsp, MaxN and mean biomass and positively correlated with mean fish length. These relationships were all according to expectations based on earlier studies.

A minor part of the variability in the structure of reef fish assemblages was explained by differences in fisheries activity, indicating that no clear fisheries effect was observed in fish assemblages in this study. Furthermore, no significant differences in average size of target species were observed between areas with different fishing pressure. However, the general absence of piscivores such as large snappers and groupers was an indication of the indelible effects of past fisheries on the Saba bank.

A total of 85 shark observations were made with Ginglymostoma cirratum as most abundant species (N=41), followed by Carcharhinus perezii (N=36), Galeocerdo cuvier (N=5) and Carcharhinus limbatus (N=3). Relatively high shark abundances (0.20 sharks hour-1) were observed on the Saba bank compared with other Caribbean regions (The Bahamas: 0.14 sharks hour-1, Belize, 0.17 sharks hour-1). Shark abundance (CPUE) was positively correlated with habitat complexity, whereas depth exerted a negative influence on shark abundances. High shark numbers are a good sign for the health of the Saba Bank ecosystem, since sharks are apex predators, making them a prime indicator for ecosystem health.

Besides ‘traditional’ measures, ecomorphology was presented as an alternative measure in explaining variation in reef fish assemblages. For ecomorphological analysis insight in trophic morphology was obtained by using a Fish Food Model (FFM). The FFM in this study quantitatively related properties of 14 marine food types to morphological characterics of 15 common fish species on the Saba bank and predicted the capacity of utilizing these food types for each species. Strong differences in morphology and little overlap was observed for all different fish species in the FFM-analysis, which was mainly explained by two sets of variables involving predatory and herbivorous lifestyle. By multiplying each species’ capacity of using food types with its abundance an ecomorphological profile of each fish assemblage was calculated. On a functional level reef fish assemblages showed less variability than on species composition level, this possibly is an indication for high levels of robustness in niche differentiation in reef fish communities on the Saba bank.

In the Dutch Caribbean EEZ, at least 27 elasmobranch species have been documented. Of these, 9 are listed as “critically endangered” and 8 as “near threatened” by the IUCN. Elasmobranchs are not a target fishery in the Dutch Caribbean, but do occur as bycatch in artisanal fisheries. Sharks are considered nuisance species by fishermen. Most sharks caught are not discarded, but consumed locally, used as bait, or (reportedly) killed and discarded at sea on the two islands where landing of sharks is illegal (Bonaire and St. Maarten). Based on recent data, published sport diver accounts, and anecdotal accounts, it is clear that shark populations in most areas of the Dutch Caribbean have been strongly depleted in the last half century.

Summary:

Shark populations have steeply declined worldwide due to unsustainable overexploitation and in this the Caribbean region is no exception. Since the 1990s many initiatives have been developed to protect the most threatened species. Sharks play an important ecological role in tropical marine ecosystems and represent an important economic potential in the context of ecotourism. As the Netherlands has traditionally shown strong international leadership and commitment in biodiversity protection, a key ambition of the new Dutch Caribbean Nature Policy Plan 2013-2017, developed jointly with the Dutch Caribbean islands, is the effective implementation of shark protection.

This report provides the necessary review and background on which to base such an endeavour. In 2012 27 species of sharks and rays were documented to be present in a deskstudy by IMARES, and six other species were listed to be tentatively present according to the IUCN Shark Specialist Group. In 2013 three new species were documented in field surveys carried out by IMARES. For these species this report provides an overview of available scientific knowledge on life history characteristics, distribution, abundance and population status in the Caribbean. The life history characteristics of slow growth, late maturity and low fecundity make sharks very vulnerable to overfishing and reduce their ability to recover from past overfishing. Because of their life history characteristics and their coastal habitat use for specific life stages, destruction of their main habitats and nursery grounds also has a relatively large impact on shark populations.

The main threats to address in a shark protection plan are fishing mortality and habitat quality. Although directed shark fisheries are not occurring in the Dutch Caribbean, there are additional concerns to global shark populations, which are mixed-species fisheries, bycatch and Illegal, Unreported and Unregulated (IUU) fishing. Sharks do occur as bycatch in artisanal fisheries in the Dutch Caribbean and illegal fishing by foreign vessels also occurs occasionally.

Public environmental awareness and support for management measures are a key determinant for the successful implementation of a shark protection plan. As part of this research a questionnaire was distributed amongst three key coastal resource user groups: fishermen, sport divers and local residents. It appeared there was no consensus on the perception of the change in biodiversity and abundance of sharks and rays. However, a decisive majority of the respondents was in favour of shark protection and half of the fishers was in favour to manage bycatch. Respondents were asked to rank specific measures in order of importance. The most appreciated measure for fishermen was enforcement including meaningful penalties and the most appreciated measures for the other respondents were a ban on shark finning and landing of sharks, followed by enforcement and immediate release of bycatch. However, in the opinion of some fishermen sharks are considered a pest, which are not specifically targeted, but when caught are consumed or sold like any other fish. Awareness raising of especially fishermen and children was added by several divers and residents as an important additional protection measure.

Throughout the world, sharks are playing an increasingly important role in island economies as an important natural attraction for eco-based recreation and tourism. A recent study has shown that a single shark can represent an average touristic resource value of US$ 2.64 million. Consequently, shark protection is taking flight around the world, including the Caribbean. In the last 3 years the region has seen the implementation of shark National Plan Of Action (NPOA) in the Bahamas, Honduras and Venezuela. Because the most destructive industrial-scale fishery practices (directed shark fisheries, shark finning, long-lining and gillnetting) have never been important in the Dutch Caribbean, the development and effective implementation of a shark NPOA is much simpler than in most situations. The overall feasibility for successful shark conservation are high due to a number of other factors listed in this report. 

Worldwide the use of sanctuaries is the main conservation tool. We therefore propose the establishment of a shark sanctuary as the main cornerstone to a Dutch Caribbean shark NPOA. This report outlines the ecological arguments for the establishment of a shark NPOA and sanctuary(ies), as well as the typical issues that need to be addressed. Legal designation of a shark sanctuary would form the first and most important step which provides the framework for all broader (international cooperation) and in depth (knowledge and conservation development) initiatives. Once a sanctuary is established, the fuller implementation of a shark NPOA should be seen as a gradual process, involving development of knowledge, policy, rules and regulations, public and stakeholder participation. In this, the Netherlands would follow and importantly reinforce the efforts of other nations who have already established NPOAs based on shark sanctuaries within the region.

The most promising area for establishment of a shark sanctuary is the little-fished Saba Bank as this area of unique biodiversity has the best shark population status, has recently already acquired national protected status and an active management structure, as well as international status as an EBSA and PSSA including IMO anchoring prohibition. Furthermore, a shark sanctuary for this area could importantly reinforce government plans to locate the first (part) of a Dutch Caribbean Marine Mammals Sanctuary at the Saba Bank. The shark population present presents unique research opportunities that could also generate considerable economic spin-off for the islands in terms of scientific research and knowledge development.

Management Recommendations:

• Develop a simple and holistic shark NPOA based importantly on the use of one (or more) shark sanctuaries
• Set up a shark research program combining on the one hand low tech opportunistic approaches (allowing participation of stakeholder groups for awareness and community support) and on the other hand using high tech approaches (genetic, telemetry, video-monitoring) to allow thorough insights even though abundance may be low
• Start actively participating in regional shark conservation and ecosystem initiatives and seek active collaboration with sister sanctuaries of the region (Venezuela, Honduras, Bahamas) 

This month’s issue focuses attention on the conservation efforts on the Windward side of the Dutch Caribbean. On St. Maarten, these days sharks are protected by law, largely due to the determination of the Nature Foundation. Their Shark Research Project is aimed at determining whether these protective measures have the desired effect and shark numbers are indeed rising again. On Saba and St. Eustatius James Ackerman and Raymond Tremblay of the University of Puerto Rico have continued their long-term population viability study of two beautiful and rare orchid species in order to produce management recommendations to save these species from local extinction.

• ‘Research of the Month‘: Shark Research on St. Maarten (Nature Foundation)
• Orchid Research on Saba and St. Eustatius
• Overview of Research and Monitoring Efforts
• Calendar of Upcoming Events, Meetings and Workshops