ROHR and GUTHERZ: BIOLOGY OF MERLUCCWS ALB1DUS 



STANDARD LENGTH [millimeters) 



FIGURE 10. — Length-weight relationship of Merluccius albidus 

 from the Gulf of Mexico. 



Larkins 1970). If such behavior is characteristic of 

 M. albidus, then it may be necessary to use both 

 mid-water trawls and higher-opening fish trawls, 

 coupled with more tows of a shorter duration. 

 More short tows will allow greater coverage of the 

 grounds and dampen inherent variability in, the 

 catch rates. This will enable us to develop more 

 realistic population estimates. 



Distribution and abundance ofM. albidus on the 

 De Soto Canyon grounds north of Tampa show 

 that the largest segment of the stock was located 

 in stratum 2 (Figure 11, Table 12). Numbers offish 

 were highest in stratum 1 (49%) but they only 

 represented 22% of the population biomass. Most 

 commercial-sized (greater than 0.45 kg) M. al- 

 bidus were caught in strata 3 and 4 (Figure 11). 



Commercial potential for this species is con- 

 sidered to be low, particularly when compared to 



BIOMASS 



STRATUM 3 

 550-639 m 



STRATUM 4 

 640-729 ffl 



FIGURE ll. — Number and biomass of Merluccius albidus by 

 90-m depth strata on De Soto Canyon slope north of Tampa, Fla., 

 June 1971. 



landings of presently exploited hake species. 

 Landings of various species of Merluccius in 1965 

 were in excess of 9.1 x 10 9 kg (Grinols and Tillman 

 1970) yet our standing stock estimate is only 

 slightly more than 3.4 x 10 6 kg and our highest 

 recorded catch was only 284 kg/h. 



Additional effort must be expended in order to 

 classify the life history and to test the hypothesis 

 discussed in this paper. Population estimates 

 must be more realistic and delineation of the 

 grounds occupied by this species more precise. 

 Merluccius albidus are known to occur from 

 Georges Bank to off the northeastern coast of 

 South America; however, presently little is known 

 concerning its population, life history, or com- 

 mercial potential. 



ACKNOWLEDGMENTS 



Richard B. Roe, NMFS, NOAA, Wash., D.C., 

 assisted in developing the computer program to 

 calculate the length-weight equations. D. Nolf, 

 Rijksuniversiteit Gent, Belgium, supplied the 



TABLE 12. — Standing stock estimates of both weights and numbers for Merluccius albidus on the De Soto Canyon slope north of Tampa, 

 Fla.; estimates are based on 19 5-h tows made in June 1971 using a 40-m fish trawl with 3-m bracket doors. 



Number Area Total 



Stratum Depth Area of sampled catch 



number (m) (hectares) samples (hectares) (kg) 



Biomass Number of 



Mean Biomass Percent estimate 2 individuals Percent 



density 1 (kg x 10 6 ) biomass (kg x 10 6 ) x 10 6 individuals 



'Values in kilograms per hectare. 

 Confidence interval = 90%. 



157 



