Assessing fisheries

While investigating catch of seahorses all over the world, we have become very involved in assessing a range of target and indiscriminate fisheries, both small- and large-scale.

Our research has led us into fisheries on six continents, ranging from hand collecting to industrial scale trawl nets. We have conducted field studies of fisheries in more than 30 countries, from Australia to Viet Nam, publishing our work in primary journals and incorporating our findings into management recommendations and policy briefs.

Unsustainable fisheries

The vast majority of the fisheries we encounter globally are unsustainable: some are fishing far too heavily; some are catching all marine life willy nilly; some are extracting marine life in closed areas; some are supplying illegal trade; some are damaging habitats. Most are poorly managed and few are monitored. Many only persist because they are subsidised to keep them operating, whether by family earnings from other activities or by government using public funds.

Finding solutions

Our research documents the challenges in fisheries and then lays the ground work for finding the solutions, building the bridge that connects research to action. We tend to take novel approaches, as evident in our work to understand women’s fisheries and invertebrate fisheries, both of which are usually overlooked. We know that solutions exist and often just need political will.

We have gathered information and created actions plans for target fisheries that use a wide variety of methods and gears with the explicit goal of catching seahorses, among other species. We have also worked with fishers, male and female, to assess change in their fisheries over time.

Gears in fisheries that target seahorses are generally fairly selective with little effect on habitats and ecosystems. The main exception would be our discovery that modified bottom trawlers are used specifically to target seahorses in Viet Nam. Just 24 such boats operating off one small island in southern Viet Nam landed more than 100,000 seahorses per year, damaging seahorse habitats as they went.

Project Seahorse has worked primarily with small-scale fisheries who use selective gear, especially in the central Philippines. In some Philippines communities, one-quarter of the fishers in a village depend on seahorses for more than half their annual income. Although each fisher catches only a few seahorses while diving, the sheer number of people fishing scales up to large numbers of seahorses extracted. Our latest survey estimated that, nationally, more than one million seahorses are landed by skin divers and compressor divers annually.

We consult extensively with fishers, valuing their knowledge as key to understanding the evolution of fisheries extraction and management. For example, we used local environmental knowledge and satellite images to probe how small-scale fishing had evolved over six decades in the central Philippines. This work revealed increasing fishing effort and a shift from benign to damaging gear, with long term effects on corals. In discussions of seahorse exploitation, fishers generally endorse the idea of marine protected areas and minimum size limits as preferred management options. Marine protected areas are broadly valuable for many marine species and favoured in policy agendas, too.

Our work on target fisheries has extended to investigating the role of women in fisheries and to seeking ways to manage small-scale fisheries on invertebrates. We were early contributors to the realisation that women fish extensively but often invisibly, focused on gleaning for invertebrates, and that their needs are seldom considered in fisheries management. We were also early in appreciating the need to develop new means for assessing sustainable levels of the mobile invertebrates that matter greatly to women and other small-scale fishers.

By far the majority of seahorses are caught in non-selective gears, most often incidentally but sometimes as secondary catch, with enough value to influence fishing routes or timing. Our global analysis documented 21 gears (across nine gear categories) that obtain seahorses as bycatch, including gill/entangling nets, seine nets, traps and bottom trawls. Documented catch rates were low, but the incredible intensity of global fishing pressure means that more than 70 million seahorses are obtained as bycatch each year.

Our global analyses are based on field surveys of seahorse bycatch in 31 countries. For example, our research in Thailand revealed that annual seahorse catches in non-selective fisheries (primarily otter and pair trawls and gillnets) approximated 29 million individuals. As another example, our research in Viet Nam revealed seahorses are caught incidentally in five types of fishing gear – crab nets, electric shock nets, seine nets and single and pair trawls. Pair trawls reportedly caught the most seahorses in Viet Nam, at approximately 12.5 million individuals per annum.

Our investigations into seahorse bycatch have determined that bottom trawling is the greatest fishing pressure on seahorses, as on so many other species around the world. Bottom trawlers are so non-selective and destructive that protective measures have no value for threatened species caught in their nets. Trawlers in India, for example, are still catching 13 million seahorses annually even though India banned extraction of seahorses in 2001; having been obtained as bycatch, these seahorses then inevitably enter the trade, which is also illegal.

Trawler, Viet Nam. Photo by Allison Stocks / Project Seahorse
[Updated 10 June 2021]

[Updated 10 June 2021]