PhD student, Kyle Gillespie (@kylemgillespie), is studying how conservation and fisheries management can be refocused to also account for invertebrates in data-poor situations.
Marine invertebrates are the spineless creatures that form coral reefs, filter murky seas, and end up on our dinner plates as delicious meals—they are also 95% of marine animal diversity. Despite their importance, they receive little conservation or fisheries attention. This is surprising given the global growth of invertebrate fisheries over the past several decades and the critical roles they play in ecosystems.
Using a combination of field studies in the Philippines, animal growth modeling, and global analyses, Kyle is trying to find out how marine protected areas (MPAs) can be designed to better protect invertebrates and how invertebrate fisheries can achieve greater sustainability.
(Banner photo: Claudio Contreras Koob/iLCP)
The measure for marine conservation success has often been the number of fish in the sea. And this is not surprising given the importance of fish in our diets. But one kilogram of out of every five of seafood in global markets is invertebrates. So, what about the clams and shrimp and octopus? That question is more important that ever before—as finfish stocks decline, the slack is often taken up by invertebrate fisheries. And the more we learn about data-poor, small scale fisheries, the more we see the scale of unreported invertebrate catch collected by “invisible fishers”—women, children and the elderly. The goal of my research is to bring invertebrates into the conservation and fisheries conversation and to evaluate tools that result in more invertebrates in the sea.
Marine protected areas and invertebrates
MPAs are areas in the ocean where animals and their habitats receive protection from human impacts. They are the most heavily advocated tool in marine conservation but rarely have we tried to understand what MPAs do for invertebrates. I want to know three things about MPAs:
- What are the impacts of MPAs on invertebrate taxa at a global scale?
- How do we design MPAs to better suit the needs of invertebrates?
- How does protecting invertebrates impact ecological functioning in marine ecosystems?
To understand the impacts of MPAs on invertebrates, I have combed through published and grey MPA literature to find records of these taxa. Using accounts from a diverse set of locations and habitat types I’m forming a global picture of how animals like crabs, octopus, lobster, and marine snails are responding to MPAs.
Designing MPAs for invertebrates
Using a set of focused field studies in the Central Philippines, I am trying to understand the relationship between invertebrates and MPA design, management, and habitat variables. Working in 10 community managed marine protected areas, I measured invertebrate abundance inside and outside of protected areas, mapped habitats, interviewed fishers to understand their invertebrate catch and evaluated MPA management practices. Using mixed effects modeling, I have shown that invertebrates important in fisheries recover inside and immediately outside of MPAs if given enough time; including high structural complexity habitat is important for invertebrates in MPA design; and fish abundance is often a poor proxy for understanding abundance of invertebrates.
Invertebrates and ecosystem functioning
Tropical invertebrates provide countless functions in ecosystems and services valuable to humans. They filter water, create habitat, remove parasites from fish, and are food for other animals. I am interested in knowing if areas of the sea that are protected function differently than areas still fished. For each macroinvertebrate taxon I observed at my field sites in the Philippines, I used scoring criteria that included a wide variety of traits ranging from where they live, to the amount of edible protein they contain. Using multivariate analyses, I have shown that inside of protected areas, there is a shift towards coral associated, shell bearing, sessile taxa that filter feed. This work shows that MPAs not only increase the abundance of many taxa, but can also change how function and provide services.
Modeling animal growth for fisheries sustainability
Catching animals before they are able to reproduce can lead to crashes in populations. But for the vast majority of fished taxa, we lack basic information on when they are reaching maturity so we can set fisheries size limits. I am using basic animal size information to model when fished invertebrates are reaching a size in which they are biologically safe to capture. In many communities in the Central Philippines, invertebrates account for between a quarter and a third of protein intake but many fishers have reported large declines in these animals. Using size frequency data from fisher catch collected over a number of months, my colleagues and I have been able to adapt the Von Bertalanffy Growth Function to provide estimates of the optimal size to capture these animals. By adapting this methodology, I hope to increase the sustainability of data-poor fisheries by providing advice on invertebrate growth and reproduction.