The specific composition of by-catch was studied: 17 species, their presence calculated
by depth strata, month and Division, and variations in monthly yield by division in the Spanish
Greenland halibut fishery, developed in the NAFO regulated area for the period 1991-1994.
Two groups of species were identified depending on the importance of their presence in
catches: the more and less frequent species. The more frequent species were considered those
with a value of above 5 kg/h annual yield, i.e. Skate, Roundnose grenadier and Roughhead
grenadier, American plaice, Witch flounder and Redfish. Analyzing the data on a monthly basis,
however, reveals the presence of higher values of yield than other species. Some species show a
stational pattern, such as Grenadiers, Skate and American plaice, particularly in Division 3N. An
other hand, other species have increased yields in recent years.
In this fishery, the characteristic species of the demersal fisheries (Skate, American plaice)
showed a wider bathymetric distribution than that considered typical in each case.
The transfer of effort southwards (Divs.3NO) in recent years, mainly in the case of small
vessels, has meant variation in the composition and relative abundance of by-catch in this fleet