Wild-caught Fisheries Research Articles

DHA-containing oilseed: a timely solution for the sustainability issues surrounding fish oil sources of the health-benefitting long-chain omega-3 oils.

Benefits of long-chain (≥C20) omega-3 oils (LC omega-3 oils) for reduction of the risk of a range of disorders are well documented. The benefits result from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); optimal intake levels of these bioactive fatty acids for maintenance of normal health and prevention of diseases have been developed and adopted by national and international health agencies and science bodies. These developments have led to increased consumer demand for LC omega-3 oils and, coupled with increasing global population, will impact on future sustainable supply of fish. Seafood supply from aquaculture has risen over the past decades and it relies on harvest of wild catch fisheries also for its fish oil needs. Alternate sources of LC omega-3 oils are being pursued, including genetically modified soybean rich in shorter-chain stearidonic acid (SDA, 18:4ω3). However, neither oils from traditional oilseeds such as linseed, nor the SDA soybean oil have shown efficient conversion to DHA. A recent breakthrough has seen the demonstration of a land plant-based oil enriched in DHA, and with omega-6 PUFA levels close to that occurring in marine sources of EPA and DHA. We review alternative sources of DHA supply with emphasis on the need for land plant oils containing EPA and DHA.

Context-dependent Impacts of a Non-native Ecosystem Engineer, the Pacific Oyster Crassostrea gigas

The introduction of non-native species represents unprecedented large-scale experiments that allow us to examine ecological systems in ways that would otherwise not be possible. Invasion by novel ecological types into a community can press a system beyond the bounds normally seen and can reveal community interactions, local drivers and limits within systems that are otherwise hidden by coevolution and a long evolutionary history among local players, as well as local adaptation of species. The success of many invaders is attributed to their ability to thrive in a wide range of habitat types and physical conditions, setting the stage for direct examination of ecological impacts of a species across a range of habitat and community contexts. Bivalves are well-known ecosystem engineers, especially oysters, which are the target of wild-caught fisheries and aquaculture. The Pacific oyster, Crassostrea gigas, is grown worldwide for aquaculture, and is presently invading shores on virtually every continent. As a consequence, this non-native species is having large impacts on many systems, but the types of impacts are system specific, and greatly depend on substrate type, how physiologically stressful the environment is for intertidal zone species, and the presence of native engineering species. A novel type of engineering effect is identified for this non-native species, whereby it alters not only the physical environment, but also the thermal environment of the community it invades. The impacts of engineering by this non-native species will depend not only on whether it facilitates or inhibits species but also on the trophic level and ecological role of the species affected, and whether similar ecological types are found within the system.

An impediment to consumer choice: Overfished species are sold as Pacific red snapper

Concern over the collapse of many wild-caught fisheries has led to a recent focus on seafood-certification and consumer-driven support of sustainable seafood. However, such conservation strategies depend critically on the accurate labeling of seafood species in marketplaces. Pacific rockfish, a group of >60 species in the genus Sebastes, are often marketed as Pacific red snapper, but little is known about the number and identity of rockfish species sold under this name. We used a molecular approach to identify species sold as Pacific red snapper by grocery chains, local fish markets, and sushi restaurants in California and Washington. Using genetic data from two mitochondrial markers (cytochrome- b and control region), we identified seven species of rockfish ( Sebastes spp.), tilapia ( Oreochromis spp.), and one true red snapper ( Lutjanus campechanus) in our samples. Among samples identified as rockfish, 56% were identified as species listed as overfished by the National Marine Fisheries Service within the past three years. By effectively permitting all species of rockfish to be sold under a common vernacular name, state and federal agencies compromise the ability of consumers to make informed choices when buying seafood.