Developments in Aquaculture and Fisheries Science, 2006
Publisher Summary This chapter discusses the two species, Aequipecten tehuelchus (Tehuelche scall... more Publisher Summary This chapter discusses the two species, Aequipecten tehuelchus (Tehuelche scallop) and Zygochlamys patagonica (Patagonic scallop), their fisheries, and experimental results that have significance in the future development of aquaculture. The fisheries supported by these two species are radically different from each other. The Tehuelche scallop is the target of small inshore fisheries in the gulfs of northern Patagonia, and involves dredging and commercial diving. In spite of the small volumes landed, these fisheries are of considerable significance for the local economies. The Patagonic scallop fishery is an industrial operation conducted by three or four factory trawlers that process the catch at sea. Catches in the order of 50,000 tons yr -1 now rank this species among the most important scallop fisheries in the World. The Tehuelche scallop is a simultaneous hermaphrodite and is iteroparous. The Tehuelche scallop may do quick and brief swimming movements as an escape response to the predators or other disturbances.
ABSTRACT The radular morphology of Zidona dufresnei was studied by optical and scanning electron ... more ABSTRACT The radular morphology of Zidona dufresnei was studied by optical and scanning electron microscopy. We analysed the variability among and within three populations distributed along the southwestern Atlantic Ocean coast, considering the hypothesis that the isolation among populations favours adaptive phenotypic variation, which is also expressed at the radular level. Populations selected for this study differ in their maximum individual size, growth rate, size and age at maturity, and fecundity. This study provides the first analysis of the interpopulational variability of the radula of Zidona dufresnei and the first description of its morphology. Zidonia dufresnei exhibited a rachiglossate radulae composed of rows of tricuspid teeth (radular formula: 0+R+0). No differences in tooth shape among populations and sexes were observed. However, significant interpopulational differences in the height of the rachidian cusp and total length of the radula were detected. Specimens from San Antonio Bay showed the lowest values for all radular variables. Positive significant relationships between total shell length and the height of the rachidian cusp and total length of the radula were found, while the number of rows remained relatively constant regardless of size. The larger morphotypes had a longer radula because of an increase in the height of the rachidian cusp. No sexual dimorphism was observed in any morphometric variables of the radula. The results suggest that populations distributed along the Argentine Sea are homogeneous for radular morphology, despite the differences in life history traits, which may be linked to a similarity in feeding habits across populations.
A cohort of juveniles Aequipecten tehuelchus was obtained on collectors placed in the San Matı́as... more A cohort of juveniles Aequipecten tehuelchus was obtained on collectors placed in the San Matı́as Gulf in the 1997–1998 reproductive season, and was cultivated in circular lantern nets or screened plastic trays. An additional trial using the “ear hanging” method was ultimately terminated due to formation of excessive biofouling on the shells, although some growth and survival data were obtained
ABSTRACT Feeding decisions under predation risk can be a key in the life of scavenger organisms, ... more ABSTRACT Feeding decisions under predation risk can be a key in the life of scavenger organisms, and tuned recognition of predation alarm cues and flexibility in the response are fundamental. The effect of injured conspecifics on the response behavior of the whelk Buccinanops globulosum to feeding opportunities was experimentally evaluated in a Patagonian Bay (40°45′S, 64°56′W, Argentina) in September 2010. The effect of sex, size, body condition, or starvation on anti-predatory behavior was assessed. The number of B. globulosum feeding on carrion was reduced by half when damaged conspecifics were present. Smaller, lighter, and starved individuals responded less to the presence of damaged conspecifics. These results indicate that, under natural conditions, feeding avoidance after detecting damaged conspecifics is a common and important anti-predatory strategy of B. globulosum and show that morphology and starvation are significant factors in the context of the trade-off between feeding and avoiding predation risk.
Experiments on fertilization (self-fertilization and cross-mating), embryonic density, larval fee... more Experiments on fertilization (self-fertilization and cross-mating), embryonic density, larval feeding, survival and larval settlement on natural substrata were carried out in order to identify some of the basic requirements of the early life history of Aequipecten tehuelchus reared under hatchery conditions.In self-fertilization, the main developmental stages were represented by the initial stages, mainly nonfertilized oocytes and embryos going through early
Abstract Time-series of fishing position, landings, satellite-derived sea-surface temperature and... more Abstract Time-series of fishing position, landings, satellite-derived sea-surface temperature and chlorophyll a concentrations were used to relate the spatial–temporal distribution of the Argentine hake Merluccius hubbsi with seasonal oceanographic processes in San Matías Gulf. Also, the seasonal effect of fishing on the hake population structure was analysed. During summer the fleet was concentrated over the area of the frontal system, obtaining the best catch-per-unit-effort (CPUE) of hake in relatively deep waters. In autumn, the dispersion of the fleet due to a reduction in CPUE coincided with the dissipation of the front, suggesting that the distribution and shoaling of the Argentine hake is associated with seasonal thermal structures. In spring, the thermal structure of the waters and the chlorophyll a blooms seem to modulate the timing of spawning of hake, which occurs mainly in October–November. In addition, the fleet captured a higher proportion of females in the gonadal recovery stage during warm months (November–April). While winter catches (May–October) consisted mainly of males, the intense summer fishing may result in a high impact on the female population. This information is relevant to design of spatial management tools intended to provide biological sustainability to the hake fishery.
Fil: Avaca, Maria Soledad. Universidad Nacional del Comahue. Centro de Investigacion Aplicada y T... more Fil: Avaca, Maria Soledad. Universidad Nacional del Comahue. Centro de Investigacion Aplicada y Transferencia Tecnologica en Recursos Marinos "Almirante Storni". - Provincia de Rio Negro. Ministerio de Agricultura, Ganaderia y Pesca. Centro de Investigacion Aplicada y Transferencia Tecnologica en Recursos Marinos "Almirante Storni". - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Centro Nacional Patagonico. Centro de Investigacion Aplicada y Transferencia Tecnologica en Recursos Marinos "Almirante Storni"; Argentina
Journal of the Marine Biological Association of the United Kingdom, Aug 11, 2015
Understanding the variables (biotic or abiotic) controlling coastal communities is the main goal ... more Understanding the variables (biotic or abiotic) controlling coastal communities is the main goal of ecology research and it is crucial to predict how communities will evolve under the increasing pressure on coastal systems by human activities. The general aims of this study were to assess the variables affecting the distribution of the fast-growing spongeHymeniacidoncf.perlevis, and to evaluate if physical stressful conditions have an influence in the relationship betweenHymeniacidonand the sea lettuceUlva lactuca. Specifically, the aims were to evaluate the abundance patterns ofHymeniacidonandUlvaand to assess the relationship ofUlvaand physical variables on the abundance ofHymeniacidonat both intertidal and subtidal.HymeniacidonandUlvashowed opposite abundance patterns.Hymeniacidonwas more abundant in sites withoutUlva, and negatively correlated withUlvaabundance at both heights. IntertidalHymeniacidonabundance was not correlated with physical variables, but subtidalHymeniacidonwas.
Over the last two decades, an increasing interest has arisen in the responses of primary producer... more Over the last two decades, an increasing interest has arisen in the responses of primary producers to global-change drivers and, more recently, in the need to consider how those various drivers may interact. To understand how Corallina officinalis (hereafter Corallina) can be affected by future changing conditions, we investigated the short-term direct effects of co-occurring increased nutrient loads, solar radiation, and lower pH, assessing how these clustered drivers affected Corallina's overall physiological performance in a harsh Patagonian coastal environment. To describe the seasonal trend of the physiological parameters in the field, we sampled subtidal Corallina to determine their net oxygen production (NOP), pigments, and carbonate content (CC). Furthermore, we conducted seasonal 10-days experiments, simulating the conditions predicted for the year 2100 by the IPCC (RCP 8.5) —manipulating pH, nutrients, and irradiance—along with the current conditions. The pigments and carotenoids/chlorophyll-a ratio were, in general, constant in the field over the seasons; but the NOP and CC dropped in spring, when the carotenoids peaked. After the experiment, the highest carotenoid/chlorophyll-a ratio was registered in summer under both the currentand the predictedconditions and in winter under the predictedcondition. This lower physiological status was also reflected in almost all other variables. Thus, Corallina may display an acclimatation strategy to cope with high ultraviolet-radiation levels by adjusting its pigment composition to avoid photoinhibition. An understanding of how Corallina, as a habitat-forming species, will respond to future global-change may provide clues about the extent of effects on the ecosystem functions and services.
Developments in Aquaculture and Fisheries Science, 2006
Publisher Summary This chapter discusses the two species, Aequipecten tehuelchus (Tehuelche scall... more Publisher Summary This chapter discusses the two species, Aequipecten tehuelchus (Tehuelche scallop) and Zygochlamys patagonica (Patagonic scallop), their fisheries, and experimental results that have significance in the future development of aquaculture. The fisheries supported by these two species are radically different from each other. The Tehuelche scallop is the target of small inshore fisheries in the gulfs of northern Patagonia, and involves dredging and commercial diving. In spite of the small volumes landed, these fisheries are of considerable significance for the local economies. The Patagonic scallop fishery is an industrial operation conducted by three or four factory trawlers that process the catch at sea. Catches in the order of 50,000 tons yr -1 now rank this species among the most important scallop fisheries in the World. The Tehuelche scallop is a simultaneous hermaphrodite and is iteroparous. The Tehuelche scallop may do quick and brief swimming movements as an escape response to the predators or other disturbances.
ABSTRACT The radular morphology of Zidona dufresnei was studied by optical and scanning electron ... more ABSTRACT The radular morphology of Zidona dufresnei was studied by optical and scanning electron microscopy. We analysed the variability among and within three populations distributed along the southwestern Atlantic Ocean coast, considering the hypothesis that the isolation among populations favours adaptive phenotypic variation, which is also expressed at the radular level. Populations selected for this study differ in their maximum individual size, growth rate, size and age at maturity, and fecundity. This study provides the first analysis of the interpopulational variability of the radula of Zidona dufresnei and the first description of its morphology. Zidonia dufresnei exhibited a rachiglossate radulae composed of rows of tricuspid teeth (radular formula: 0+R+0). No differences in tooth shape among populations and sexes were observed. However, significant interpopulational differences in the height of the rachidian cusp and total length of the radula were detected. Specimens from San Antonio Bay showed the lowest values for all radular variables. Positive significant relationships between total shell length and the height of the rachidian cusp and total length of the radula were found, while the number of rows remained relatively constant regardless of size. The larger morphotypes had a longer radula because of an increase in the height of the rachidian cusp. No sexual dimorphism was observed in any morphometric variables of the radula. The results suggest that populations distributed along the Argentine Sea are homogeneous for radular morphology, despite the differences in life history traits, which may be linked to a similarity in feeding habits across populations.
A cohort of juveniles Aequipecten tehuelchus was obtained on collectors placed in the San Matı́as... more A cohort of juveniles Aequipecten tehuelchus was obtained on collectors placed in the San Matı́as Gulf in the 1997–1998 reproductive season, and was cultivated in circular lantern nets or screened plastic trays. An additional trial using the “ear hanging” method was ultimately terminated due to formation of excessive biofouling on the shells, although some growth and survival data were obtained
ABSTRACT Feeding decisions under predation risk can be a key in the life of scavenger organisms, ... more ABSTRACT Feeding decisions under predation risk can be a key in the life of scavenger organisms, and tuned recognition of predation alarm cues and flexibility in the response are fundamental. The effect of injured conspecifics on the response behavior of the whelk Buccinanops globulosum to feeding opportunities was experimentally evaluated in a Patagonian Bay (40°45′S, 64°56′W, Argentina) in September 2010. The effect of sex, size, body condition, or starvation on anti-predatory behavior was assessed. The number of B. globulosum feeding on carrion was reduced by half when damaged conspecifics were present. Smaller, lighter, and starved individuals responded less to the presence of damaged conspecifics. These results indicate that, under natural conditions, feeding avoidance after detecting damaged conspecifics is a common and important anti-predatory strategy of B. globulosum and show that morphology and starvation are significant factors in the context of the trade-off between feeding and avoiding predation risk.
Experiments on fertilization (self-fertilization and cross-mating), embryonic density, larval fee... more Experiments on fertilization (self-fertilization and cross-mating), embryonic density, larval feeding, survival and larval settlement on natural substrata were carried out in order to identify some of the basic requirements of the early life history of Aequipecten tehuelchus reared under hatchery conditions.In self-fertilization, the main developmental stages were represented by the initial stages, mainly nonfertilized oocytes and embryos going through early
Abstract Time-series of fishing position, landings, satellite-derived sea-surface temperature and... more Abstract Time-series of fishing position, landings, satellite-derived sea-surface temperature and chlorophyll a concentrations were used to relate the spatial–temporal distribution of the Argentine hake Merluccius hubbsi with seasonal oceanographic processes in San Matías Gulf. Also, the seasonal effect of fishing on the hake population structure was analysed. During summer the fleet was concentrated over the area of the frontal system, obtaining the best catch-per-unit-effort (CPUE) of hake in relatively deep waters. In autumn, the dispersion of the fleet due to a reduction in CPUE coincided with the dissipation of the front, suggesting that the distribution and shoaling of the Argentine hake is associated with seasonal thermal structures. In spring, the thermal structure of the waters and the chlorophyll a blooms seem to modulate the timing of spawning of hake, which occurs mainly in October–November. In addition, the fleet captured a higher proportion of females in the gonadal recovery stage during warm months (November–April). While winter catches (May–October) consisted mainly of males, the intense summer fishing may result in a high impact on the female population. This information is relevant to design of spatial management tools intended to provide biological sustainability to the hake fishery.
Fil: Avaca, Maria Soledad. Universidad Nacional del Comahue. Centro de Investigacion Aplicada y T... more Fil: Avaca, Maria Soledad. Universidad Nacional del Comahue. Centro de Investigacion Aplicada y Transferencia Tecnologica en Recursos Marinos "Almirante Storni". - Provincia de Rio Negro. Ministerio de Agricultura, Ganaderia y Pesca. Centro de Investigacion Aplicada y Transferencia Tecnologica en Recursos Marinos "Almirante Storni". - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Centro Nacional Patagonico. Centro de Investigacion Aplicada y Transferencia Tecnologica en Recursos Marinos "Almirante Storni"; Argentina
Journal of the Marine Biological Association of the United Kingdom, Aug 11, 2015
Understanding the variables (biotic or abiotic) controlling coastal communities is the main goal ... more Understanding the variables (biotic or abiotic) controlling coastal communities is the main goal of ecology research and it is crucial to predict how communities will evolve under the increasing pressure on coastal systems by human activities. The general aims of this study were to assess the variables affecting the distribution of the fast-growing spongeHymeniacidoncf.perlevis, and to evaluate if physical stressful conditions have an influence in the relationship betweenHymeniacidonand the sea lettuceUlva lactuca. Specifically, the aims were to evaluate the abundance patterns ofHymeniacidonandUlvaand to assess the relationship ofUlvaand physical variables on the abundance ofHymeniacidonat both intertidal and subtidal.HymeniacidonandUlvashowed opposite abundance patterns.Hymeniacidonwas more abundant in sites withoutUlva, and negatively correlated withUlvaabundance at both heights. IntertidalHymeniacidonabundance was not correlated with physical variables, but subtidalHymeniacidonwas.
Over the last two decades, an increasing interest has arisen in the responses of primary producer... more Over the last two decades, an increasing interest has arisen in the responses of primary producers to global-change drivers and, more recently, in the need to consider how those various drivers may interact. To understand how Corallina officinalis (hereafter Corallina) can be affected by future changing conditions, we investigated the short-term direct effects of co-occurring increased nutrient loads, solar radiation, and lower pH, assessing how these clustered drivers affected Corallina's overall physiological performance in a harsh Patagonian coastal environment. To describe the seasonal trend of the physiological parameters in the field, we sampled subtidal Corallina to determine their net oxygen production (NOP), pigments, and carbonate content (CC). Furthermore, we conducted seasonal 10-days experiments, simulating the conditions predicted for the year 2100 by the IPCC (RCP 8.5) —manipulating pH, nutrients, and irradiance—along with the current conditions. The pigments and carotenoids/chlorophyll-a ratio were, in general, constant in the field over the seasons; but the NOP and CC dropped in spring, when the carotenoids peaked. After the experiment, the highest carotenoid/chlorophyll-a ratio was registered in summer under both the currentand the predictedconditions and in winter under the predictedcondition. This lower physiological status was also reflected in almost all other variables. Thus, Corallina may display an acclimatation strategy to cope with high ultraviolet-radiation levels by adjusting its pigment composition to avoid photoinhibition. An understanding of how Corallina, as a habitat-forming species, will respond to future global-change may provide clues about the extent of effects on the ecosystem functions and services.
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