Climate change may affect crab populations by affecting embryo development and incubation.
To test this, we measured the embryonic development and incubation duration of 11 blue golden crabs. 3 [+ or -]0. 45, 4. 3 [+ or -]0. 31, and 6. 1 [+ or -]0. 61[degrees]C.
Every two weeks the embryo area, length and width, eye length and width and egg yolk percentage are measured from digital images, and hatching larvae are collected from individual crabs every day.
Data were compared between eggs of the same age (
Weeks after fertilization).
Temperature has no significant effect on embryo measurement, but does affect the developmental index (
Percentage of egg yolk and eye size).
Incubation was significantly delayed at cold temperatures, about 46-
Day difference 2. 3[degrees]C to 6. 1[degrees]C.
The development length is temperature-related through a power function, ranging from 410 [+ or -]8 days at 6. 1[degrees]C to 434 [+ or -]11 days at2. 3[degrees]C.
Incubation duration from 40 【+ or -]4. 6 days at2. 3[degrees]C to 55 [+ or -]6. 2 days at 6. 1[degrees]C.
Using quadratic equations, a model was developed to predict incubation dates from the eye index.
Embryo development ar 4. 3 and 6. 1[degrees]
C. arrested between 35 and 50 weeks;
This evidence, coupled with other behavioral observations, suggests that crabs may be able to regulate development to partially compensate for temperature changes.
Key words: Blue king crab, Duck mouth beast, decapoda, anomura, incubation, embryo development, temperature introduction, blue king crab (BKC)
Platypus (Brandt, 1850)
In the Pacific waters of Alaska, Japan, and Russia, it is a commercial-value shellfish.
The decline in Alaska led to the closure of commercial fisheries in the Pribilof Islands and St.
Since 1999 (NPFMC 2002).
Other crab species in Alaska, including Red Emperor crab (RKC)
Paralithodes camtschaticus (Tilesius, 1815)
In the past three years, there have also been great fluctuations.
Among the several explanatory assumptions put forward, the most plausible ones include highly variable youth recruitment related to climate change (
Zheng He Kruse 2000)
, And indirect effects of spatial distribution of adults on larvae survival (
Loher & Armstrong2005).
Female BKC is sexually mature at age 96.
3mm long (CL)
There are only 80 in the Pribilof Islands. 6 mm at St. MatthewIsland (
MacIntosh ton & MacIntosh 1983).
The female BKC of the Bering Sea has a reproductive cycle once every two years (
Jason and Armstrong 1985) samerton and Macintosh 1989.
Adult females have molt, mate, and super-fertilized embryos during late winter or early spring (
ToMatch, February).
It takes 13 months for embryo development and 12 identifiable stages (Stevens 2006a).
The larvae hatch in the late spring (Matchto April)
It takes about 30 days for each woman (Stevens 2006b).
Women carry empty egg boxes in the following year until they spawn again in the spring of the following year (
MacIntosh ton & MacIntosh 1985).
Incubation is a crucial early event in the life of king crab, and the incubation time may have a significant impact on their survival.
Zoe1 zoea of RKC must find sufficient sources of food such as diatoms (
Thallasiosira sp. )
Feed will be poor within 3 days of incubation or survival (Paul et al.
1989, Paul and Paul 1990).
In the case of a particularly low water temperature, the incubation of RKC was delayed for several years (Otto et al.
1990, Shirley and others. 1990).
The time of Hatching does not match the existence of food sources (e. g.
Flowering of plankton)
Could lead to subsequent hunger and yearsclass failure (
Cushing ort 1914, kuhin 1990).
Recent studies have shown a clear warming trend in the Bering Sea.
Land and stability 2004).
In the cold years covered by normal sea ice from 3 to April, there were obvious early outbreaks of plankton in spring, while in the years with higher temperatures (
And no ice)
Flowering of plankton was delayed until June (Stabeno et al. 2001).
Therefore, early incubation of crab seedlings is likely to be more likely to match the food source due to elevated temperatures.
To study the effects of climate change on crab recruitment process, we raised blue king crabs at three different temperatures to determine the effect of temperature on embryo development rate and incubation time.
In particular, we would like to know if an increase in temperature can lead to faster development and a shorter duration.
Materials and methods the crab-treated female BKC was captured near the Pribilof Islands (between 56[degrees]54' and 57[degrees]
Between 35 'N and 16 9 [degrees]18' and 169[degrees]30' W)
Use side September 2003-
Load the crab pot on board and return to the Dutch port AK.
The crab is then packed with gel ice wet sacks and shipped to toKodiak in a large cooler;
After arriving at Kodiak, they were arranged in a4, 000-
L 4 [circulating cooling seawater tankdegrees]C.
All crabs were measured from the right track to the rear center edge of the shell (
Shell length (CL)
Use the cursor calipers.
All female rabbits hatched larvae in the spring of 2004 (Stevens 2006b)
Spawn or spawn again until next winter.
On January 2005, 12 female crabs were randomly divided into three groups, 4 in each group, and placed in frozen seawater.
[2, 4 or 6 points]degrees]C (
Hereinafter referred to as 2C, 4C, 6 Ctreatments).
These temperatures are chosen because they contain a change in depth --
The average temperature of the Bering Sea continental shelf in 1998-2004 (
Land and stability 2004).
Crabs in 2C and 6 treatments were placed at 2,500-
L can, 4C crab 4,400 ina-L tank.
There are a small amount of each tank (