The Vancouver Aquarium Marine Science Centre is proud to welcome newly hatched black rockfish larvae – a first here for the Aquarium. A few weeks ago a pregnant black rockfish was spotted in the Pacific Canada Pavilion. Our marine biologists regularly see pregnant copper rockfish, but it was a first for the black rockfish. It is impossible to tell males from females unless one gets pregnant, so they weren’t able to accurately identify the mix between the genders.
Recently four black rockfish were moved into the Pacific Canada exhibit from their usual home in the Treasures of the BC Coast gallery to allow them more space to swim. It’s believed at least one of those black rockfish was a male that resulted in the recent pregnancy.
Black rockfish and other rockfish species mate and produce offspring in the fall through spring. They have internal fertilization with the females holding onto the eggs until they hatch upon which time she’ll give birth to up to a million little larvae. Black rockfish live up to 50 years old but don’t become reproductive until they’re between six to eight years old. This late reproductive onset leaves rockfish susceptible to overfishing which can have devastating effects on their populations. The Vancouver Aquarium has been instrumental in helping establish rockfish conservation areas so these fish can live and reproduce in protected areas.
The researchers here in the Fish Research Lab are working towards finding ways to feed the rockfish larvae by raising zooplankton and feeding the zooplankton different diets to make sure the larvae get all the nutrients they need. Feeding studies are carried out using randomized block design scientific studies to determine which diet treatments work well and which ones don’t. We measure survival rates and development stage to decide which diets work the best. We have been able to produce over 100 juvenile copper rockfish over the years – some of which can be seen in the exhibits in Pacific Canada. These new black rockfish larvae allow us to try our zooplankton diet for the first time with this fish species.
Raising our own fish at the Aquarium helps us to protect the dwindling population of rockfish off the coast of B.C. Our goal is that one day someone can use this research to develop sustainable Ocean Wise rockfish aquaculture.
In addition to developing methods to raise black rockfish larvae in our research lab, we have also transplanted juvenile rockfish to new areas such as Point Atkinson to help re-establish dwindling populations. Our efforts have been successful, and we are seeing the black rockfish become established.
Keep an eye out for this important west coast fish species on your next visit to the Aquarium. If you’re a local scuba diver, you can help rockfish conservation by assisting us with our next rockfish abundance survey which will begin in the summer of 2015. For more information or questions about the annual rockfish survey visit us online, or contact a member of the research team at: 604-659-3780 or via email [email protected].