Friday, December 25, 2009

Lobster Egg Collection

Drs. Heather Koopman and Andrew Westgate and their two dogs and one cat arrived at the research station for two weeks in December, Dec. 7-21. This is the second December they have been on Grand Manan, having experienced most months on the island with the exception of the coldest winter months.

Heather has been monitoring lobster egg production and viability in female lobsters of all sizes. This means she has to go out on lobster boats and when a berried female (a female carrying eggs on the underside of her tail) comes up in a trap, Heather measures and collects a few eggs for lab analysis of lipids or fats. The amount of lipid in an egg gives an indication of the fitness of the female, more lipid also means the egg has a better chance at survival because of more stored energy available to it during development. The berried female is carefully returned to the water with a notch on her tail, indicating if she is caught again, after releasing her eggs, that she was a berried female and will be released. The notch stays in the tail for several moults before growing back in. The reproductive cycle in lobsters is long - two years.

Heather put in some long days, often leaving the wharf at 4 AM and one day, not getting back until midnight. These are hours that lobster fishing often put in, 14+ hour days are not unusual. While there are more berried females in June in the traps, the December samples are important to the overall trends. She was pleasantly surprised by a large blue lobster, a rare colour in lobsters.

For a comical look at inshore lobster fishing (and also what a berried female lobster looks like), check out or and look for the segment "Rick and Lobster Fishing".

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