Cabinza Grunt

Isacia conceptionis, the "cabinza", is a grunt of the family Haemulidae that lives in shallow waters over rocky and sandy bottoms of the southeastern Pacific, from Peru to Chile ^[1]. It is a commercial fishery resource, and in Peru its catch is regulated by a minimum size of 19 cm total length ^[2]. The International Union for Conservation of Nature lists it in the Least Concern category ^[3].

Cuvier described the species in 1830 as Pristipoma conceptionis, in volume 5, page 268 of the Histoire naturelle des poissons by Cuvier and Valenciennes ^[4]. The WoRMS record now accepts it as Isacia conceptionis, placed in the genus Isacia, which Jordan and Fesler established in 1893 ^[4].

It is a benthopelagic marine fish that lives over rocky and sandy bottoms between 0 and 50 m depth ^[1]. It is distributed in the southeastern Pacific, from Peru to Chile, and FishBase also lists a record from Nicaragua ^[1].

In Cortés and Aron's work on the cabinza of Coquimbo, the range is given as between the Lobos de Afuera islands in Peru and Corral in Chile ^[5]. That study used fish caught by handline at La Herradura, a bay of Coquimbo, at 29°59' S ^[5]. In Peru, a 2010 to 2011 study examined fish bought at the Chorrillos fishing terminal in Lima ^[6].

The reproductive information comes from La Herradura bay, on the Chilean coast. Each month from April 1995 to March 1996, 30 fish were taken by handline; of the 360 fish obtained, the ovaries of the 280 females were analysed ^[5]. Those females measured 18 to 32 cm total length and weighed 130 to 400 g ^[5].

Histological analysis recognised five of the six ovarian maturity stages of the scale used, and mature and hydrated ovaries held oocytes at several stages of development at once, so the cabinza is a batch spawner ^[5]. Mature females were present all year except in April, and hydrated ovaries were recorded only in June and July and in February and March ^[5]. The authors interpret this as two spawning seasons, a main and longer one between spring and summer and a smaller one in winter ^[5].

Mean batch fecundity in 10 mature females was 122,595 eggs, with a range of 45,195 to 199,996 eggs per female ^[5]. It was best fitted by a power function of total length, F = 0.0003 LT raised to 3.9701, and of total weight, F = 0.2255 PT raised to 1.1539, with r2 of 0.797 and 0.798 ^[5]. The condition factor was above 1 for much of the year ^[5]. The IMARPE report summarised in the 2019 Peruvian norm estimated the length at first gonadal maturity at 17 cm total length ^[2].

According to FishBase, the cabinza eats polychaetes and algae as well as small crustaceans, among them isopods and amphipods, and its estimated trophic level is 2.9 ^[1].

Its parasite fauna was studied in 123 fish from the Chorrillos fishing terminal in Lima, collected between December 2010 and March 2011 ^[6]. A total of 95 parasites of seven species were counted, a mean abundance of 0.77 parasites per fish ^[6]. Those standing out for prevalence and mean abundance were Choricotyle isaciencis, Corynosoma obtuscens, Proleptus carvajali and Clavella simplex ^[6]. The prevalence of Choricotyle isaciencis increased with the total length of the host fish ^[6].

The IUCN assessment of Isacia conceptionis, dated February 2009, places it in the global category of Least Concern ^[3].

In Peru, Ministerial Resolution 416-2019-PRODUCE, published on 8 October 2019, sets for the cabinza a minimum catch size of 19 cm total length and a maximum tolerance of juveniles of 15 %, replacing the 21 cm and 10 % set by R.M. 209-2001-PE ^[2]. The norm cites a report by the Instituto del Mar del Perú that describes the Peruvian cabinza stock as fully exploited ^[2]. It also tasks that institute with monitoring the main biological, population and fishery indicators of the resource and with informing and advising the Ministry of Production, among other things, on the period and percentage of increase relative to the maximum tolerance for incidental catch of juveniles ^[2].

FishBase states that the species is used in commercial fisheries ^[1]. In Chile, Cortés and Aron report that the cabinza is sold by both the artisanal and the industrial sectors, and that its largest national landing in the decade of 1990 was more than 648 t in Coquimbo in 1991 ^[5].

In Peru, the 2019 norm includes it among the marine fish with a minimum catch size, which shows it is a resource the State regulates and whose monitoring it entrusts to the Instituto del Mar del Perú ^[2]. Cortés and Aron suggest that the gap between their fecundity estimate and that of an earlier Chilean study could point to inadequate management of the exploitation, making regulation of the fishery urgent ^[5].