REPORT 141, DECEMBER, 1998
PELAGIC RESOURCES HYDROACOUSTIC EVALUATION CRUISE, RV HUMBOLDT
AND RV JOSE OLAYA BALANDRA 9808-09 FROM PAITA TO LOS PALOS (TACNA)
MEASUREMENTS IN SITU OF TS OF SEVERAL SPECIES DURING THE WINTER OF 1998 CRUISE
OF THE RV HUMBOLDT 9808-09
GUTIERREZ, MARIANO AND NALDI HERRERA
measurements of TS were made during 108 trawl catches of echo-trace confirmation, carried out by the RV Humboldt during the Hydro-acoustical Assessment of Pelagic Resource Cruise 9808-09. Only those casts where more than 90% of the catch belonged to a single species were the ones considered for the analysis. The factors b20 of the TS equation (TS=20 log L- b20) that have been determined, which should be considered as provisional, are the following one: Pacific Cutlassfish (Trichiurus lepturus)= 70,95 (120kHz); Panama Lightfish (Vinciguerria lucetia pacifici) = 83,29 (120kHz); Longnose Anchovy (Anchoa nasus)= 86,57 (120kHz); Mackerel (Scomber japonicus)= 83,09 (120 kHz); Pacific Cutlassfish (Trichiurus lepturus)= 71,41 (38 kHz); and Panamá Lightfish (Vinciguerria lucetia pacifici)=82,04 (38kHz).
STANDING OF THE MAIN PELAGIC RESOURCES IN THE PERUVIAN SEA DURING
THE POST-NIÑO 1997 - 1998 PERIOD.
ÑIQUEN, MIGUEL; ALEJANDRO ECHEVARRIA, RICARDO TAFUR, MARILU BOUCHON,
ROSA DÁVALOS, JAVIER QUIÑÓNEZ, SANDRA CAHUÍN AND DAVID VALDEZ
An evaluation cruise to assess pelagic resources stock in Peruvian waters was carried out during the months of August and September 1998. The results showed important variations on the spatial distribution of the resources, on its concentrations and on the size structure. The Peruvian anchovy (Engraulis ringens) biomass continues on low levels and its decrease is highly correlated with salinity and low plankton volume. Other mesopelagic and demersal resources increased their biomass such as Vinciguerria, Lump-tail Sea-robin, and the Peruvian sea-catfish. The juvenile rate of most fishes was high and indicated a total renewal of their populations. The size structure of anchovy changed drastically compared with previous cruise reports. There was a dominance of juvenile group with average length in 6,15cm. The recruitments in sardine, jack mackerel, and mackerel continued to be good. Since Fall 1998, during Post Niño conditions, the anchovy spawning continued. In addition we include some notes about cephalopod distribution.
REPRODUCTIVE STATE OF THE PERUVIAN ANCHOVY, ENGRAULIS RINGENS; PERUVIAN
SARDINE, SARDINOPS SAGAX SAGAX AND CHUB MACKEREL, SCOMBER JAPONICUS
PERUANUS, DURING THE RESEARCH CRUISE IN THE RV HUMBOLDT 9808-09.
BUITRÓN, BETSY AND ENRIQUE MECKLENBURG
The reproductive state of the Peruvian anchovy, Engraulis ringens; Sardine, Sardinops sagax sagax and Chub Mackerel, Scomber japonicus peruanus, was analyzed using histological methodology, between August the 20th and September the 18th 1998, according to latitudinal areas. Results from the samples were considered at capture time by latitudinal degree. In the area between 14°S and 18°S, the anchovy was found in spawning state, while the sardine was also found spawning between the 9°S and 12°S degree of latitude. Chub Mackerel was found in a maturing stage. Anchovy fecundity was estimated in 14,137 oocytes per spawning batch per female.