Comparative study of fecundity of latitudinal variation in fecundity and reproductive investment of Lithodes santolla in the Argentinian Sea

Supervisor: Gustavo Lovrich (Centro Austral de Investigaciones Científicas, CADIC, Ushuaia – Tierra del Fuego. Argentina)
Marine invertebrates inhabiting deep-sea and Arctic and Antarctic waters are subjected to low temperatures and poor and unpredictable food conditions. In order to survive to these conditions, marine invertebrates develop adaptive features, which involve an accurate adjust of the reproductive strategy among others. Hypothesized characters comprised in this adjustment are an increase in egg size with latitude and a consequent decrease in fecundity. Lithodid crabs inhabit high latitudes and at deep waters. Particularly the Southern King Crab, or Lithodes santolla has a wide distribution latitudinal range in the southern tip of South America, living in both Atlantic and Pacific waters. Ovigerous females from three different localities, from different latitudes (Golfo San Jorge 45-47°S, Tierra de Fuego Atlantic coast 51-54°S and the Beagle Channel 55°S) of the Argentinian Sea were used for comparison. Size of individuals, fecundity, egg and embryo sizes, and water and lipid relative content of egg mass, hepatopancreas, ovary and muscle were measured. Fecundity and size of reproductive females were correlated at the three locations, and this correlation did not vary between sites. Egg volume also varies contrary to what was expected, and significant bigger egg values were registered from Golfo San Jorge. Also, although females from Golfo San Jorge had lower percentages lipid contents in the hepatopancreas and ovary, relative content of water and lipid contents in egg masses were similar among localities. All these significant differences between populations show that the reproductive strategy of L. santolla is adaptive to different environments. However, this adaptive potential may response to different parameters, others than latitude.