Egg lipids - Determination and practical application of egg quality measures toward reliable culture of high-value marine finfish species

There is increasing global awareness of the need for sustainable aquaculture. Aquaculture represents a potential mechanism for supplementing wild fish harvests, either through stocking of cultured animals or farming to market size. In the first case, stocked animals would be available to sport and commercial fishermen. In the latter, consumer demand would be met directly with a farmed product, reducing pressure on wild stocks. By the year 2030, the global population is projected to reach 8.2 billion, with an expected demand for seafood of 150 million metric tons (mmt), 54 mmt of which the Food and Agriculture Organization (www.fao.org) estimates that aquaculture must contribute.

Meanwhile in the U.S., an astounding 86% of the seafood consumed is imported ($9 billion annually), which makes seafood second only to oil as the largest natural resource contributor to our national trade deficit. There remains a great need for U.S. aquaculture production to fill the seafood void. Commercial-scale production of marine finfish in the U.S. is limited to a handful of species, however, including red drum, Pacific threadfin, cobia, cod, and flounder (excluding the anadromous Atlantic salmon), and production is often inconsistent. On the U.S. West Coast, many native marine species represent good potential candidates for aquaculture. Most of these, such as California sheephead, California halibut, cabezon, lingcod, white seabass, and rockfishes, are fully or over-exploited by capture fisheries. Other high-value species like California yellowtail and yellowfin tuna are transitory, with apparently healthy populations, but based on success elsewhere in the world, are believed to offer excellent potential for commercial aquaculture development in the U.S. A major step in the creation of a viable and profitable marine aquaculture industry lies in developing reliable fingerling production, and central to this is understanding the variables that determine egg and larval quality. The lack of knowledge in what optimizes egg and larval quality is an important limiting factor in developing culture techniques for any species (Kjorsvik et al. 1990; Bromage 1995). Inconsistent or poor egg quality significantly affects the production and viability of larval and juvenile fish. In the absence of high-quality eggs, it is not possible to optimize husbandry practices because larval performance is substandard under typical culture conditions, such as high stocking densities, aggressive weaning regimes, and grading or other handling procedures.

Unfortunately, identifying simple indicators of egg quality has been difficult as no individual metric is universally applicable within and among species. This proposal seeks to identify easy-to-use indictors, as well as determine pre- and post-spawning factors that affect egg quality, in up to three very different ecologically and economically valuable marine fish species native to the U.S. West Coast: a highly-pelagic finfish, the California yellowtail (Seriola lalandi; CYT); a deep-sea whitefish, the sablefish (Anoplopoma fimbria; SF); and/or a semi-resident benthic flatfish species, the California halibut (Paralichthys californicus; CH). All three species are multiple batch spawners, producing large numbers of eggs several times over the course of a spawning season. Defining the differences between high and low quality eggs and documenting correlations between quality and different conditions (e.g. broodstock diet, age, domestication status, spawning methods, or progression through the spawning season) will directly impact the success of culturing species like these. If inferior batches of eggs can be identified early on, culturists would have a valuable tool, which would significantly advance mariculture development along the U.S. West Coast and elsewhere by leading toward consistent fingerling production of species with great potential for culture.

Fatty acid profiles of marine fish egg lipids.

Tags: doc/noaa/nmfs/nwfsc, efs (environmental and fisheries sciences) division, national marine fisheries service, noaa. u.s. department of commerce, non-noaa funded, northwest fisheries science center
Organization: National Oceanic and Atmospheric Administration, Department of Commerce