Virtual Posters

In this study we examined the demersal fish species Leatagonus decagonus (Atlantic poacher) collected form fjords around Svalbard. It is a commonly encountered species in coastal waters of Svalbard, often found on depths around 350 m. They tolerate wide temperature fluctuations and are found in waters with temperatures ranging from -1.7 to 4.4 °C. They are not however found in waters with salinities t preference outside the spawning season, giving a domination of one sex in our sampling areas. Our results suggest sexual dimorphism in size. Females were longer (10.2-15.6 cm, mean=13.2 cm) than males (10.6-13.9 cm, mean=12.1cm). Females were also heavier (4-12 gram, mean=7.4) than males (3-10 gram, mean=5.81 g). Both length and weight was significantly different between the sexes (p= 0.011 and p= 0.027, respectively). There was no significant difference in age distribution between the sexes. However, males had a wider age distribution (2-14 years) than females (3-7 years). The majority of specimens were 4-7 years old (mean = 4.9 years). Both sexes had a length-weight relationship that gave a negative isomorphic body condition, indicating energy priority towards reproduction rather than tissue growth. The females were overall larger than males with age. There was an overall differentiation in size of the liver between the sexes with males having larger liver indices than females. These results may suggest male parental care as males that watch over eggs do not get to feed much and therefore store energy in the liver for this purpose. Alternatively, females may put so much energy in the eggs that they do not have the ability to build up energy stores like the males. There was little variation in gonadosmatic index with length and age, indicating that most of our specimens were mature. Thus, both females and males are mature by the age of 4. L. decagonus produce relatively few (2'976–4'854 eggs, but at least half the eggs in each gonad were undeveloped) big and lipid rich eggs, which suggest that there is some sort of parental care. This is usually true for species with relatively low fecundity. Pelagic postlarvae found in June were big and well developed, typically for species with K-strategy.