Jack Ashton tells the stories of several vulnerable marine species that are recovering.

The oceans; mysterious, beautiful, and vaster than we can possibly imagine. Without them we could not survive. Equally as important are the extraordinary species within; from the vampire squid to the basking shark. However, they face threats on unprecedented levels. Many scientific research papers tell of marine conservation successes, but these are rarely transferred into media content. In the news, all we hear about is the destruction we are causing; but, unfortunately, this alone does not necessarily change peoples’ attitudes. Persistent reminders of the damage already caused can lead to some people thinking that there is little point in actively trying to save the marine realm, as it is past the point of no return. We need encouragement. We need to know of projects which are succeeding, demonstrating to us that we can turn this around, and our efforts can pay off. This is why I would like to tell the stories of several examples, showing that many organisms residing within our oceans are recovering.

Firstly, a relatively well-known example is the green turtle; a species in which many populations have demonstrated quite remarkable recoveries. Their historical threats came mostly from harvesting for both meat and eggs, and more recently this has been intertwined with threats from coastal development and entanglement in nets. To see a massive recovery, however, we need look no further than Alagadi beach in Cyprus, a nesting site for green turtles. In 1992, there was a 90% nest predation rate, meaning that 90% of the eggs laid by green turtles here were either harvested or eaten by predators. After a ban on harvesting and the initiation of the work done by the Marine Turtle Conservation Project, nest predation rate is now below 5% and the number of green turtles nesting on protected beaches has increased dramatically. This is a hugely positive outcome. Emily Hunter, a student at the University of Exeter who volunteered here, has said “I think it’s so easy to get disheartened with conservation goals, but after spending so much time and effort working towards the protection of these endangered animals, it really feels like you made a difference which is reflected in the data from the last decade”. It is very easy to presume that our efforts do not make much of a difference due to what we see in the news, but green turtles are a fine example of how we can help endangered marine species to recover.

Shark populations are notoriously depleted, and for the most part, they show continuous reductions due to severe overfishing. Therefore, it is extremely easy to think that sharks will inevitably go extinct; so, it may come as a surprise to hear that there are multiple populations of great white sharks that are recovering. Great whites off New England in the USA, for example, declined to about 30% of their historical population in the 1970s and 80s due to demand for their fins. After regulations were created to prohibit fishing for them, though, their abundance here has exceeded 70% of historical populations. This is just one of many shark species that are recovering around the USA; others include sandbar, blacktip, tiger and spinner sharks. What adds to this good news is that none of these species have shown these recoveries after a total ban on fishing; they are simply due to the improved management of fisheries. This shows that all is not lost and we can help sharks to recover to near-historical levels. All it may take is other countries implementing equally as effective management strategies to offset the extremely negative consequences that overfishing has on these vital apex predators.

White's seahorse, also known as the Sydney seahorse, is endemic to the Southwest Pacific, from Sydney to the Solomon Islands, and is classed as endangered. This is largely due to coastal development and pollution, which has resulted in severe habitat degradation and loss. However, this is a story about the success of marine protected areas (MPAs) – one of the most widely adopted methods of attempting to conserve areas of the ocean. The protection that MPAs provide have helped to anchor populations of White’s seahorse and halt the decline, which is a great success for these delicate animals. Further to this, there are various projects aiming to increase populations of this species, such as captive breeding programmes. One that is particularly unique is the ‘seahorse hotel’ project in Australia. Within this project, an artificial habitat is provided for White’s seahorses in cases when a suitable, non-damaged habitat is unavailable. This gives them a refuge which will, hopefully, not be damaged like their natural habitat has been. There has been a resounding success in the early stages; these ‘hotels’ can indeed support a great number of seahorses, and has led to increases in seahorse abundance in the locations that they are established.

The surf redfish, contradictory to its name, is a species of sea cucumber that is vulnerable to extinction. Although potentially insignificant looking, this strange animal is extremely valuable to ecosystems. Naturally occurring in large numbers, their eggs provide food for other species, while they also filter water, improving its quality, and recycle nutrients back into the food web. Their biology is fascinating; when under extreme stress they, quite literally, eviscerate themselves. During this process, these sedentary beings expel cuvierian tubules and holothurin through their anus, a toxic chemical with the ability to kill animals in the vicinity. As a result, surf redfish are rarely on many species’ menus – except the menus of humans. Along with other sea cucumber species, they are, unfortunately, threatened heavily by legal, and illegal, harvesting for the Asian delicacy Bêche-de-mer (the boiled, dried and smoked flesh of sea cucumbers). Strangely, it is described as having ‘little to no taste’, and sand must be carefully washed out of it before is it intensely infused with ingredients to make it palatable. Mostly, the largest individuals are harvested from coral reefs on dramatic scales, which has caused reductions in populations and reduces the mature population which is able to reproduce. The good news for these underrated animals, though, is that better management and ceasing of harvesting has led to recoveries in many locations. In Tonga, the overall population density is increasing and in Fiji, a capture assessment found that the per cent of individuals caught that are above the mature length and mass have both notably increased to around 40%, not far from natural levels. This will, if management remains in place, increase the population as there will be a greater proportion able to reproduce. This is extremely good news, and has hopefully put us on the path to retaining this species that is so underrated, yet important to their marine environment.

These are just some of the many examples of successes in a world of marine destruction. ‘Oceans can be successfully restored by 2050’, is what one recent research paper has suggested, providing we all do our part. It is possible, and we can succeed. However, there is a great bias towards conserving the ‘flagship’ or ‘charismatic’ species, such as green turtles, great white sharks or White’s seahorses all mentioned in this article, but we must not ignore the, perhaps, less attractive species, such as the surf redfish. All play their part in sustaining the oceans, integrating into intricate food webs and ecosystem services. In turn, these systems sustain us, so we must not forget about any species. One final, overall success is that the percentage of marine species assessed by the IUCN that are threatened with extinction has reduced, from 18% in 2000 to 11.4% in 2019. This, surely, offers huge encouragement. We must remember the damage we cause, but this must not override the successes that we can initiate, too. Every little thing that one can do to help is a huge win for the retention of an incredible species. If we play our part, there is a chance that we can turn things around, before it is too late.

Hope for marine species

Jack Ashton tells the stories of several vulnerable marine species that are recovering.