The drastic curbing of the formerly massive poaching of sea turtles on Boa Vista’s beaches during the last almost one and a half decades is a conservation success story in Cape Verde. However, sea turtles are not only hunted on the beaches – they are not safe in the sea either. On the one hand, they fall victim to industrial fishing in large numbers as unintentional bycatch. But also the local, artisanal fishing takes its toll, because traditionally sea turtles are not spurned there and therefore, in contrast to industrial fishing, are hunted specifically. It can even be assumed that this problem is currently increasing, precisely because the protection of turtles on the beaches is so successful. As a result, it is now increasingly worthwhile to meet the remaining demand for turtle meat by hunting at sea, which is much more difficult than on the beaches. However, since fishermen at sea are currently not controlled, it is difficult to estimate the true extent of poaching at sea so far. However, we must assume that this is a significant threat to stocks. Since 2018, we have been working closely with the marine conservation organization MarAlliance to address this issue as well. To this end, we are currently pursuing two main approaches:
Exploring the nearshore mating grounds and migratory pathways of the loggerhead sea turtle off Boa Vista
In order to be able to successfully protect the turtles at sea, it is of course important to know where they mainly occur there. The nearshore mating areas are of particular interest. This is where male and female turtles meet in high density in a relatively confined space for a limited period of time, after having migrated there for a long time from the sometimes very distant feeding grounds where they spend most of their lives.
At these places the mating of the turtles takes place a few weeks before the egg-laying until the actual nesting season. Not only do many animals then move in a confined space, but unfortunately in the hormonal rush they also lose their typical alertness and readiness to flee, and they can therefore be particularly easily preyed upon. We therefore need to know and map the mating grounds as precisely as possible in order to know where to protect the turtles. The focus of protection measures such as sea patrols can be narrowed down even further in light of the fact that not all of the mating grounds are regularly used by fishermen, but only those areas where they find their actual target species. In the vastness of Boa Vista’s coastal waters, these areas of overlap between the turtles’ mating grounds and the main activity of artisanal fishing can then be targeted and effectively protected.
An initial approach to mating range research was undertaken by Alexander “Zeddy” Seymour of MarAlliance in 2018. The study used underwater video as well as systematic observations at the water surface on previously defined transects to record the abundance of turtles in the monitoring area. Furthermore, fishermen were interviewed about their observations and the location, type, and duration of their activity. The results provided a preliminary assessment on the use of coastal areas off nesting beaches, including the overlap of loggerhead sea turtle mating areas with artisanal fisheries. A 2018 interim report on the project strongly recommended that local fishermen be better involved in sea turtle conservation. Unfortunately, the project was temporarily interrupted by the tragic death of Zeddy Seymour in the summer of 2019 and the onset of the Corona pandemic in 2020, but was then able to continue with adjustments to the new situation beginning with the 2020 nesting season.
A popular target of poaching at sea are male turtles. Their penis is traded expensively as a supposed aphrodisiac. Since the males, unlike the females, never leave the water, they can only be caught there. The male sea turtles are clearly outnumbered by the females and due to the special breeding biology it is to be feared that with the climate warming the sex ratio will develop further to the disadvantage of the males, until finally too few males are present to be able to fertilize all females successfully. Therefore, the targeted killing of males poses a serious threat to the population. Another project therefore involves researching the whereabouts and migration routes of male turtles using satellite transmitters. A first turtle was still transmitted by Zeddy Seymour in June 2019, and we were able to monitor its migration routes into January 2020. Three more turtles were tagged in 2020 with the help of MarAlliance staff. All three animals continue to provide valuable data into the present (as of May 2021)! Two animals, like the animal tagged in 2019, move over a wide area in the open oceanic waters between Boa Vista and the west coast of mainland Africa. Of particular interest, however, is the behavior of one male that not only has not left the waters around Boa Vista, even after almost a year now, but has barely moved more than a few kilometers from where it was captured since then. We are already very excited about the evaluation of the results!
Increased cooperation with the fishermen of Boa Vista as part of our social engagement
Partnerships with local fishermen can provide a practical way to better interact with fishermen overall and encourage greater participation by fishermen in sea turtle conservation and research. There are approximately 70 fishing boats on Boa Vista that operate in the nearshore waters. In order to involve the fishermen in our project work, we started a cooperation with initially six fishermen who help us with data collection in the sea and with the tagging of turtles. In return, they received safety equipment for their boats and work clothes with individual motifs of sea creatures such as octopuses, whales and, of course, turtles. With this first step, we very much hope to pave a way for trustful cooperation with the local fishermen, which will benefit both the fishermen and the sea turtles.
However, another very big problem for turtles is industrial fishing on the high seas, to which thousands of turtles probably fall victim each year; we have referred to this before in a post (link). We are currently in discussion with a working group to reduce bycatch of seabirds and sea turtles off the coast of West Africa, involving MAVA, BirdLife International, and other international and resident organizations.