The relationship between numbers of fish attracted to baited cameras and population density: Studies on demersal grenadiers Coryphaenoides (Nematonurus) armatus in the abyssal NE Atlantic Ocean

Abstract

The number of Coryphaenoides (Nematonurus) armatus attracted to baits ( N peak) at depths of 2000–5000 m in the NE Atlantic Ocean is shown to vary with fish density ( n km −2) in accordance with the equation: N peak = dn x (1− exp((−c exp(−nk)−m)x)) where c=350, d=4.095×10 −3, k=0.0037, m=10, x=0.005 which predicts a dome-shaped relationship with a maximum number observed at intermediate population densities. This results from more rapid arrival of fish at high densities being offset by shorter staying times in the food-rich environment of high-density localities. Caution is advised when using attraction of fish to baited cameras as an index of stock abundance.