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

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 x 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. (C) 1998 Elsevier Science B.V. All rights reserved.