Abstract Farfantepenaeus brasiliensis (Latreille, 1817) and Farfantepenaeus paulensis (Pérez Farfante, 1967), commonly known as pink shrimps, are two commercially important penaeid species caught by artisanal and industrial fisheries in the Southwestern Atlantic Ocean. The currently known southern distribution for F. brasiliensis extends to Rio Grande do Sul (Brazil), while F. paulensis reaches the coastal waters of Buenos Aires (Argentina), although Uruguay represents the southern limit of commercial captures for the latter. In the shrimp season of 2019 (February-May) the presence of F. brasiliensis was recorded together with F. paulensis in the brackish coastal lagoons of Uruguay (34º30’ to 34º50’S). A total of 143 specimens of F. brasiliensis and 152 of F. paulensis were analyzed evaluating morphological, morphometric and genetic differences. The presence of both species was validated based on morphological differences and sequencing the Cytochrome Oxidase I (COI) mitochondrial gene. Significant morphometric differences were found between both species, particularly, the larger rostral length in relation to the carapace and cephalothorax length in F. paulensis compared to F. brasiliensis. To our knowledge, this is the first confirmed record and commercial catch of F. brasiliensis in Uruguayan waters. This southwards expansion could be explained by extending climatic variability events associated with prolonged periods of positive sea surface temperature anomalies in the region. Given the potential commercial relevance of the species, a better understanding of the southward expansion of F. brasiliensis into Uruguayan waters would be helpful in developing efficient management and conservation strategies under a scenario of increasing water temperatures.

ABSTRACT This work analyzed length-mass relationship, growth in length, mass variations and dynamic of yolk sac depletion of Mustelus schmitti embryos, extracted from females catched by the artisanal fishery acting off La Paloma (34°39'S, 54°10'W, Uruguay) during 2006 and 2007. Differences in total length and total mass between sexes were not significant. Embryos showed a negative allometric growth for both years with a slope change near the day 170 of the year, likely to be associated with the depletion of the external yolk sac. Gompertz and Von Bertalanffy curves were adjusted for each year. Parturition date was determined around the day 300 of the year. Yolk depletion followed a logistic dynamic Yt=1/(1+e(-13.749 + 0.072*t)) for 2006 and Yt=1/(1+e(-10.472 + 0.054*t)) for 2007. Embryos showed a mean increase in total dry mass of 5.4g in 187 days which, together with yolk depletion dynamics, indicates additional energetic supply, suggesting that M. schmitti presents limited histotrophy.

RESUMEN Este trabajo analizó las relaciones largo-masa, crecimiento en talla, variaciones en masa y dinámica de consumo del saco vitelino de embriones de Mustelus schmitti extraídos de hembras capturadas por la flota pesquera artesanal del puerto de La Paloma (34°39'S, 54°10'W, Uruguay) durante 2006 y 2007. Las diferencias en largo total y masa total entre sexos no fueron significativas. Los embriones mostraron crecimiento alométrico negativo en ambos años, con un cambio de pendiente cercano al día 170, probablemente asociado con el agotamiento del saco vitelino externo. Se ajustaron curvas de crecimiento de Gompertz y VonBertalanffy para cada año. La fecha de parición se determinó cerca del día 300 del año. El consumo de vitelo siguió una dinámica logística Yt=1/(1+e(-13.749 + 0.072*t)) en 2006 y Yt=1/(1+e(-10.472 + 0.054*t)) en 2007. Los embriones mostraron un aumento promedio de masa seca de 5.4g en 187 días, esto, junto con la dinámica de consumo de vitelo, indicó una provisión adicional de energía, sugiriendo que M. schmitti presenta histotrofía limitada.

ResumoO camarão rosa Farfantepenaeus paulensis (Pérez Farfante, 1967) distribui-se ao longo da costa atlântica do Brasil (Bahia) até a Argentina (Mar del Plata). Os estágios larvais entram na primavera-verão nas lagoas salobras do Uruguai associados com correntes de maré, onde a água dominante é da Corrente do Brasil. Nesses ambientes, o crescimento é acelerado e no início do outono geralmente atinge o tamanho comercial, apoiando importantes pescarias regionais. A captura de camarão foi analisada nas lagoas costeiras uruguaias entre 1988 e 2013 e relacionadas com os fenômenos da variabilidade climática em eventos ENSO e com elementos da dinâmica populacional da espécie. A captura total variou entre 0,7 e 162 ton. A variação das capturas apresentou relação negativa com os eventos de variabilidade climática causados pelo El Niño. Os parâmetros de crescimento analisados originaram valores de L ∞ = 177 mm (comprimento total) e K = 1,48 no período 2009 -2013. Esses valores sãoligeiramente diferentes dos calculados para populações naturais no sul do Brasil, o que sugeriria a existência de uma mesma população, implicando na necessidade de coordenação pesqueira entre os dois países.

AbstractThe pink shrimp Farfantepenaeus paulensis (Pérez Farfante, 1967) is distributed along the Atlantic Coast from Bahia (Brazil) to Mar del Plata (Argentina). The larval stages enter the Uruguayan brackish water lagoons during late spring to summer associated with tidal currents of the Brazilian Current. In such environments the growth is accelerated and in early autumn the individuals attain commercial size, supporting important regional artisanal fisheries. The pink shrimp catches from 1988 to 2013 were analyzed and related to phenomena of climate variability in ENSO events and to the growth of the species. The total catch ranges from 0.7 to 162 tons. The variation in catches has a negative relationship with the varied climatic events caused by El Niño. Growth parameters yielding values of L ∞ = 177 mm (total carapace length) and K = 1.48 for the period 2009-2013. These values differ slightly from those calculated for natural populations in southern Brazil, suggesting that the population is the same and thus implying the need for coordinated fisheries management between the two countries.