Acanthistius Patachonicus
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456 NOAA First U.S. Commissioner National Marine Fishery Bulletin established 1881 of Fisheries and founder Fisheries Service of Fishery Bulletin Abstract—The Argentine sea bass Early life history of the Argentine sea bass (Acanthistius patachonicus) is one of the most conspicuous and abundant (Acanthistius patachonicus) (Pisces: Serranidae) species in the rocky-reef fish assem- blage of Northern Patagonia, which 1 sustains important recreational Lujan Villanueva Gomila (contact author) and commercial activities, such as Martín. D. Ehrlich2,3 scuba diving, hook-and-line fish- Leonardo A. Venerus1 ing, and spear fishing. We describe the morphological features of eggs, Email address for contact author: [email protected] larvae, and posttransition juveniles of A. patachonicus and summarize 1 abundance and distribution data Centro Nacional Patagónico (CENPAT) for larvae collected on the Argen- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) tine shelf (between ~40°S and 44°S). Boulevard Brown 2915 Eggs and yolk-sac larvae came from Puerto Madryn an in vitro fertilization experiment. Chubut, U9120ACD Argentina Larger larvae were distinguished by 2 Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP) relevant morphological features, in- P.O. Box 175 cluding the development of the oper- Mar del Plata cular complex and head spination, Buenos Aires, B7602HSA Argentina meristics, and pigmentation pattern. 3 Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA) The early stages of A. patachonicus CONICET are similar to those of the koester Facultad de Ciencias Exactas y Naturales (A. sebastoides) and of the western Universidad de Buenos Aires (UBA) wirrah (A. serratus), the other 2 spe- Intendente Güiraldes 2160 cies of Acanthistius whose larval de- Ciudad Universitaria velopment has been described. The Ciudad Autónoma de Buenos Aires, C1428EGA Argentina body and head in A. patachonicus were moderate in size, but its pre- anal length was long. The particular head spination pattern of larvae of A. patachonicus, namely a few con- spicuous smooth spines (mainly on the preopercle and opercle), and 2 The genus Acanthistius, included in Northern Patagonia (Galván et al., posttemporal spines, was useful for the speciose family Serranidae (Nel- 2009), where it sustains commercial, differentiating this species from oth- son, 2006; but see Smith and Craig, recreational, and sport activities like ers and, therefore, made it possible 2007), is represented by 2 species in scuba diving and hook-and-line and to describe the whole developmental the Southwest Atlantic Ocean: Acan- spear fishing. In offshore waters, it series and to link the early stage morphological features to those of thistius brasilianus, which ranges is caught by coastal and high-seas adults. from 15°S (Brazil) to 36°S (Uruguay) fleets, partly as bycatch in fisheries (Irigoyen et al., 2008) and Acanthis- that target Argentine hake (Mer- tius patachonicus, which ranges from luccius hubbsi) and Argentine red 23°S in Brazil to 48°S on the Argen- shrimp (Pleoticus muelleri). Commer- tine shelf (Irigoyen et al., 2008), at cial annual landings of A. patachoni- depths of 0–100 m (Cousseau and cus decreased between 1989 (14,509 Perrotta, 2000). Until recently, A. metric tons) and 2013 (2462 metric Manuscript submitted 5 November 2014. patachonicus was misclassified as A. tons) (MAGYP1). Manuscript accepted 18 August 2015. brasilianus, giving rise to a nomen- Despite the large economic and Fish. Bull. 113:456–467 (2015). clatural confusion in the ichthyologi- recreational values of this species, Online publication date: 10 September 2015. cal literature from Argentina. Irigoy- there is little information about its doi: 10.7755/FB.113.8 en et al. (2008) clarified the taxonom- reproductive ecology and behavior. ic status of the species of Acanthis- tius in the Southwest Atlantic Ocean 1 MAGYP (Ministerio de Agricultura, Ga- The views and opinions expressed or nadería y Pesca). 2013. Total landings implied in this article are those of the and developed a new diagnostic key to discriminate between these taxa. of marine catch by species and month. author (or authors) and do not necessarily Ministerio de Agricultura, Ganadería y reflect the position of the National Acanthistius patachonicus is the Pesca, Argentina. [Available at web- Marine Fisheries Service, NOAA. most abundant rocky-reef fish in site, accessed November 2014.] Villanueva Gomila et al.: Early life history of Acanthistius patachonicus 457 What we know is that A. patachonicus is a long- collected monthly during a 2-year survey that we con- lived (maximum age recorded for fish ~47 cm in total ducted) aboard outboard motorboats in the SJG, cover- length was 40–41 years, see Rubinich, 2001), slow- ing a regular grid of 25 stations, from October 2011 growing fish that reaches 65 cm in total length and through March 2012 and from September 2012 through 4 kg in weight (Irigoyen et al., 2008). It is a dioe- April 2013 (Table 1; Fig. 1). No samples were available cious partial spawner and fertilization is external. for January and November 2012 within the SJG. In The spawning season of this species extends between addition, 105 ichthyoplankton samples were collected September and December off the coast of Buenos Ai- during 2 surveys, CC-01/08 and EH-05/11, conducted res province and in Northern Patagonia (Ciechomski by the Instituto Nacional de Investigación y Desar- and Cassia, 1976; Dell’Arciprete et al., 1987), where rollo Pesquero (INIDEP, based in Mar del Plata, Ar- at least a fraction of its populations congregate in gentina) in December 2008 and November 2011 aboard massive spawning aggregations (Irigoyen2). No data the RV Capitán Canepa and RV Eduardo Holmberg, about its early life stages are available in the scien- respectively. tific literature. Ichthyoplankton tows were made with Hensen nets In this study, the development of A. patachoni- with mouth diameters of 70 cm (CONCACEN, SJG), cus from the egg stage to the posttransition juvenile multinets (CC-01/08) with square mouths (50×50 cm), stage (sensu Vigliola and Harmelin-Vivien, 2001) is and bongo nets (EH-05/11) with mouth diameters of described, and the distinctive features of its early 60 cm, all fitted with 300-μm mesh. General Oceanics3 life stages are compared with those of other species (Miami), Hydro-Bios (Altenholz, Germany), and T.S.K. of Acanthistius. In addition, abundance and distribu- (Tsurumi-Seiki Co., Ltd., Yokohama, Kanagawa, Ja- tion patterns of larvae in the San Matías Gulf (SMG) pan) flowmeters were mounted in the mouths of the and San José Gulf (SJG), in Northern Patagonia, and nets to estimate the volume of filtered water. Towing in adjacent waters are presented. Beyond a purely sci- speed ranged between 77 and 154 cm/s. During the entific interest, identification of the early stages of A. research cruise CONCACEN 2009, 2 plankton tows (1 patachonicus will help to identify spatial and temporal oblique tow (depths sampled: 5–172 m) and 1 horizon- patterns in reproduction and, in turn, will shed light tal tow (depths sampled: 1–20 m), were made at each on the location of spawning and nursery grounds for station. During the 2 surveys in the SJG, tows were this species. oblique tows (depths sampled: 7–52 m) or horizontal tows (depths sampled: 3–28 m), depending on bottom depth, to increase the volume of water sampled. Hor- Materials and methods izontal tows were made a few meters below the sur- face when conducted aboard the RV Puerto Deseado Collection of samples and close to the bottom of the seafloor when conducted aboard motorboats within the SJG. Tows were horizon- Eggs and yolk-sac larvae came from in vitro fertiliza- tal during the survey CC-01/08 (depths sampled: 0–57 tion. Ripe adults were caught by trawling near the m) and oblique during the survey EH-05/11 (depths mouth of SMG (41°45′S 63°28′W) on 11 November sampled: 9–60 m). Maximum depth for each ichthyo- 1978, on board the RV Walther Herwig. Hydrated oo- plankton tow was recorded by depth sensors attached cytes and sperm were mixed in a bucket with saltwa- to the nets (Table 1). Water temperature was recorded ter. Later, the fertilized eggs were washed and trans- with sensors coupled to the nets or with conductivity, ferred to 2-L buckets containing seawater at 18°C. At temperature, and depth (CTD) sensors (during sur- approximately every 2 h over the course of a week, a veys CC-01/08 and EH-05/11, water temperature was variable number of eggs (between 16 and 39 eggs) and recorded with a SBE 25 Sealogger CTD and SBE 19 yolk-sac larvae (between 1 and 47 larvae) in different SeaCAT Profiler CTD [Sea-Bird Electronics, Bellevue, developmental stages were taken from the buckets and WA], respectively). fixed in 5% formalin. Samples were fixed immediately after collection and Aboard the RV Puerto Deseado on the Argentine preserved in 5% formalin. Larval abundance was ex- shelf in November 2009, 41 ichthyoplankton samples pressed as the number of larvae/1000 m3. were collected during the research cruise CONCACEN Only one posttransition juvenile was available, and 2009, which was conducted by the Consejo Nacional de it was used for the description of that stage. This speci- Investigaciones Científicas y Técnicas (CONICET) and men was caught near Mar del Plata, Argentina, in De- the Servicio de Hidrografía Naval and also involved the cember 1963 in a bottom shrimp net at a depth of less Centro Austral de Investigaciones Científicas (CADIC) than 30 m. No further details were found on the label and Centro Nacional Patagónico (CENPAT) (Table 1; to identify the collection lot (ichthyoplankton collec- Fig. 1). Another 212 ichthyoplankton samples were tion, INIDEP, uncataloged). 2 Irigoyen, A. J. 2014. Personal commun. Centro Nacional Patagónico (CENPAT), Consejo Nacional de Investigaciones 3 Mention of trade names or commercial companies is for iden- Científicas y Técnicas (CONICET), Puerto Madryn, Chubut, tification purposes only and does not imply endorsement by U9120ACD Argentina.