This paper investigates a means of detecting the reaction of aquatic vertebrates to environmental change by recording behavioral patterns within the diurnal activity. An apparatus measuring the activity of Jordanella floridae, Goode and Bean, using a photoelectric sensor system is described. Individual sensors monitored specific areas of the test aquarium that had special significance to the fish in the way of a particular behavioral category. An event recorder documented the breakage of light beams, giving continuous and accurately timed data of activity. Two distinct patterns of activity were recognized; a control, or typical, pattern, and a pattern resulting from the administration of a large (10°C) change in environmental temperature. Modifications in the diurnal behavior were consistent with reactions that could be adaptive for the species under similar conditions in nature.

No description available.

The objective of this study was to evaluate the impact of extreme acidic and alkaline pH excursions of fish populations in streams receiving fly ash settling basin effluent. Fish communities were sampled above and below the effluent outfall in a mountain stream, Adair Run, adjacent to the coal-fired Glen Lyn Power Plant in southwestern Virginia. This effluent, which exhibited a pH increase of up to pH 9.3 as the basin nearly filled, contributed to a downstream decline in species diversity and an increased dominance of the stoneroller (Campostoma anomalum), which displaced more sensitive species. Laboratory avoidance studies, utilizing a steep-gradient trough apparatus, were used to investigate the potential role of avoidance behavior that may alter fish distributions in acidic and alkaline waters. Stonerollers, rainbow trout (Salmo gairdneri), golden shiners (Notemigonus crysoleucas) and spotfin shiners (Notropis spilopterus) exhibited first significant avoidance responses to continuously decreasing pH conditions at pH 6.0-7.0, well above the 96-hr LC50 values of 4.05 and 4.24 for trout and golden shiners, respectively. When the pH was gradually increased, avoidance thresholds of pH 9.5- 11.0 were observed, beyond the 96-hr LC50 values of 9.13 and 8.86 for trout and golden shiners. Single acute alkaline exposures initially yielded more rapid avoidance responses, with acclimation to alkaline conditions frequently occurring within 30 minutes. Gill histological alterations, as observed by transmission electron microscopy, were detected following exposure to extreme pH excursions, with more rapid changes occurring with alkaline exposures. Gill tissue showed marked recovery within 8-14 days. / Master of Science

In response to anthropogenic pressures that have degraded habitat and put marine resources at risk (Leslie et al., 2003; Mumby et al., 2001; Puniwai et al., 2003), there has been a growing interest in the use of marine protected areas (MPAs) as a management tool to help slow, prevent or reverse negative anthropogenic changes. Recent studies have shown that the most effective MPAs are those which represent a full range of habitat types (Leslie et al., 2003; Carr et al., 2003). Yet, available scientific research has not evaluated the near-shore marine habitat utilization along the West Coast of Hawaii at the large-scales utilized by resource managers. Thus, this study focused on identifying the regional habitat utilization patterns for selected Hawaiian reef fish species to determine the most effective combination of habitat types. In addition, the habitat utilization analysis was used as one of several case studies to test the ArcGIS Marine Data Model���s (MDM) (Wright et al., 2001) adaptability to work with real-world data and perform real-world analyses, as well as meet the five goals outlined by the MDM Working Group (Wright et al., 2001). Created in 2001, by researchers from Oregon State University, Duke University, NOAA, the Danish Hydrologic Institute and ESRI, the MDM is a geodatabase template tailored to meet the needs of the marine GIS user community. Ultimately, this analysis will aid marine managers as it establishes correlations between small and large-scale habitat information, which provides a regional look at habitat utilization. Also, by testing the functionality of the MDM, its strengths and weaknesses will be identified so that it can be improved to better serve the marine GIS user community. / Presentation date: 2004-06-08 / Graduation date: 2005

D.Phil. / The endocrine system regulates important physiological processes in an organism. Numerous natural and synthetic chemicals are released into the environment and can disrupt the normal functioning of the endocrine system, influencing physiological processes even at relatively low concentrations. These chemicals are known as endocrine disrupting chemicals (EDCs). These compounds are highly persistent in nature due to a resistance to biodegradation, and because of their hydrophobicity. EDCs bio-accumulate especially in the fatty tissue of aquatic and terrestrial organisms. Developmental and reproductive disorders are potentially harmful effects of exposure. EDC sources include agricultural and urban runoff, and industrial effluent discharges that eventually pass through sewage- and wastewater treatment plants. These chemicals degrade at various rates and to varying extents during treatment processes, forming many new chemicals. Methods to predict the occurrence of endocrine disruption include the occurrence of intersex, and changes in spermatogenesis and secondary sexual characteristics (SSCs) of supposedly exposed organisms. The urogenital papilla (UGP) is a SSC whose development and morphology is hormonally controlled and may be influenced when exposed to EDCs. The sharptooth catfish (Ciarias gariepinus) is often used in environmental toxicity studies. Sex is determined by the external dimorphic UGP found only in males. Intersex has been observed in this species in South African freshwater systems. A field study was carried out in the Rietvlei (RVD) and Marais (MD) dams in the Rietvlei Nature Reserve (RNR). MD acts as a sedimentation dam before water enters RVD, and is theoretically more polluted. The RNR system receives effluent from various domestic and industrial sources including agriculture, industries, informal settlements and municipal sewage treatment plants. Four sampling surveys, two low and two high flow, were carried out over a period of two years. Supposedly male catfish (n=97) were collected and identified as male or possible intersex based on the UGP. Water and sediment was collected for target EDC and endocrine disrupting metal (EDM) analyses. Fish length and mass, and UGP length and width were measured. Laparotomy was performed and gonads were inspected macroscopically for alterations. A section of the gonad and the entire UGP was removed and processed according to standard techniques for histological analysis. The gonadosomatic- (GSI), hepatosomatic- (HSI) and UGP length (UGPLI) indices were calculated. Fish fat was removed and analysed for target EDCs.

Turbidity is an important measurement of water quality, considering it describes water clarity and is an indirect indicator of light transmittance in the water column. Turbidity may impact fish that rely on vision to forage by affecting ability to search for prey. Largemouth bass (LMB; Micropterus salmoides) is a visual predator that may have lower foraging success resulting in reduced growth, reproduction, or survival under conditions of high turbidity. I conducted a field experiment in Wolf Lake, Mississippi to assess impacts of turbidity on diet and distribution and a laboratory experiment with manipulated turbidity levels (0 – 250 NTU) to assess foraging efficiency of LMB. There were no significant relationships between turbidity and diet or distribution in the field study. However, there were significant effects of turbidity on foraging efficiency in laboratory trials. These results indicate that assessing turbidity is important to manage LMB in systems susceptible to high turbidity levels.

Submitted by Maria de Lourdes Mariano (lmariano@ufscar.br) on 2017-01-06T18:42:53Z No. of bitstreams: 1 BIAGIONI_Renata Cassemiro_2015.pdf: 2035608 bytes, checksum: fac86d235f6f4d30c63014e045fdafb1 (MD5) / Approved for entry into archive by Maria de Lourdes Mariano (lmariano@ufscar.br) on 2017-01-06T18:45:49Z (GMT) No. of bitstreams: 1 BIAGIONI_Renata Cassemiro_2015.pdf: 2035608 bytes, checksum: fac86d235f6f4d30c63014e045fdafb1 (MD5) / Approved for entry into archive by Maria de Lourdes Mariano (lmariano@ufscar.br) on 2017-01-06T18:45:56Z (GMT) No. of bitstreams: 1 BIAGIONI_Renata Cassemiro_2015.pdf: 2035608 bytes, checksum: fac86d235f6f4d30c63014e045fdafb1 (MD5) / Made available in DSpace on 2017-01-06T18:46:03Z (GMT). No. of bitstreams: 1 BIAGIONI_Renata Cassemiro_2015.pdf: 2035608 bytes, checksum: fac86d235f6f4d30c63014e045fdafb1 (MD5) Previous issue date: 2015-06-30 / Não recebi financiamento / In Brazil, species introduction in freshwater ecosystems has become an important topic in conservation ecology, as it is one of the main causes of biodiversity loss. Invasive species benefiting from the lack of natural enemies outside their original geographic distribution might represent a highly competitive pressure to the native species sharing the same resources of the invaded areas and may lead to changes in the abundance and richness of natural communities. In this sense, for a better understanding of these relationships, it is possible to study experimentally the interactions between invasive and native species evaluating competition effects. So, the objective of this study was to assess, through an experimental approach, if there is intraspecific and interspecific competition between two cichlid fish: a native species, the cará Geophagus brasiliensis and the exotic Nile tilapia Oreochromis niloticus. The objective was to examine if there is differential growth and feeding under different fish densities in consortium or separated. The experiment was conducted in Setor de Aquicultura do Polo Regional Vale do Paraíba - APTA Regional in the municipality of Pindamonhangaba, from March to June 2014. In order to assess the intraspecific competition of each species due to increased density and, comparing them with interspecific competition when the two species coexist in the same tank, five treatments with four replicas were considered. Fish diet studies suggest that there was no intraspecific and interspecific competition for food in this experiment. Despite the morphological similarities between the two fish species, the weight gain is evident and it can be assigned to the treatment itself. Intraspecific competition was not detected, as there was no significant decrease in the average weight gain for both species with increasing density of individuals of the same species. As for the interspecific competition, the results suggest that space availability may have been the main factor of dispute between species, since there was no significant change in diet and the consortium of these species benefited O. niloticus in much higher proportion than G. brasiliensis. / No Brasil, a introdução de espécies em ecossistemas aquáticos continentais se tornou um tema de grande relevância na área de ecologia da conservação, pois está dentre as principais causas da perda direta da biodiversidade. As espécies invasoras, beneficiadas pela falta de inimigos naturais fora da sua distribuição original, representam uma elevada pressão competitiva para as espécies nativas das áreas invadidas que partilhem os mesmos recursos, podendo levar a alterações na abundância e riqueza nas comunidades envolvidas. Neste sentido, para melhor entendimento dessas relações, é relevante estudar as interações entre espécies invasoras e nativas bem como avaliar os efeitos da competição. O objetivo deste estudo foi avaliar, através da abordagem experimental, se há competição intraespecíficas ou interespecífica entre duas espécies de ciclídeos: a espécie nativa de cará Geophagus brasiliensis e a exótica tilápia do Nilo Oreochromis niloticus. O experimento foi conduzido no Setor de Aquicultura do Polo Regional Vale do Paraíba - APTA Regional, município de Pindamonhangaba, no período de março a junho de 2014. Para avaliar as competições intraespecíficas das espécies, em virtude do aumento da densidade, comparando-as com a competição interespecífica quando as duas espécies coexistem no mesmo tanque, foram considerados cinco tratamentos, com diferentes combinações e densidades, com quatro réplicas. Os resultados obtidos com o estudo da dieta dos peixes sugerem que não houve competição intraespecífica ou interespecífica por alimento nas condições deste experimento. Quanto ao ganho em peso, verificou-se que a diferença entre G. brasiliensis e O. niloticus, apesar das semelhanças morfológicas entre si, é notória e pode ser atribuída ao tratamento em si. Não foi possível constatar a existência de competição intraespecífica, pois não houve diminuição significativa do ganho médio em peso, tanto para o cará quanto para a tilápia, quando aumentada a densidade de indivíduos da mesma espécie. Já quanto à competição interespecífica, os resultados obtidos sugerem que o espaço pode ter sido o principal fator de disputa entre as espécies, uma vez que não houve alteração significativa na alimentação e o consorciamento dessas espécies beneficiou O. niloticus em proporção muito maior que G. brasiliensis.

Poenskop Cymatoceps nasutus (Pisces: Sparidae), an endemic South African sparid, is an important angling species being predominantly targeted by the recreational shore and skiboat sector. This species is slow-growing, long-lived, late-maturing and sex-changing, making poenskop acutely sensitive to over-exploitation. Despite interventions, such as the imposition of size and bag limits (currently 50 cm TL and one per licensed fisher per day) by authorities, catch-per-unit-effort trends reflect a severe and consistent stock decline over the last two decades. Poenskop has been identified as a priority species for research and conservation. Although the biology and population dynamics of this species have been well-documented, little is known about the movement behaviour of poenskop. Furthermore, there is a complete lack of information on its genetic stock structure. This thesis aimed to address the current knowledge gaps concerning movement behaviour and genetic stock structure of poenskop, making use of a range of methods and drawing on available information, including available fishery records as well as published and unpublished survey and research data, and data from long-term monitoring programmes. Analysis of available catch data (published and unpublished) revealed a decline in the number of poenskop caught as well as size of fish taken over the last two decades, ultimately reflecting the collapse of the stock (estimated to be at 20% of their pristine level). Improved catch-per-unit-effort data from the Tsitsikamma National Park Marine Protected Area (MPA), and larger poenskop being caught in the no-take areas than adjacent exploited areas of the Pondoland MPA confirmed that MPAs can be effective for the protection and management of poenskop. The current MPA network in South Africa is already wellestablished, and encompasses considerable reef areas, being preferable for poenskop habitation. Conventional dart tagging and recapture information from three ongoing, long-term fishtagging projects, conducted throughout the poenskop’s distribution, indicated high levels of residency at all life-history stages. Coastal region, seasonality and time at recapture did not appear to have a significant effect on the level of movement or distance moved. However, on examining the relationship among coastal movements and fish size and ages, larger and older fish (adults) moved greater distances, with juveniles and sub-adults showing high degrees of residency. An estimation of home-range size indicated smaller poenskop to hold smaller home-ranges, while larger poenskop hold larger home-ranges. Large easterly displacements of a number of adult poenskop is in accordance with previous findings that this species may undertake a unidirectional migration up the coastline of South Africa where they possibly settle in Transkei waters for the remainder of their lives. This high level of residency makes poenskop vulnerable to localised depletion, although they can be effectively protected by suitable MPAs. Despite considerable tagging effort along the South African coastline (2 704 poenskop tagged with 189 recaptures, between 1984 and 2010), there remains limited information on the connectivity of different regions along the South African coastline. This was addressed using mitochondrial DNA sequencing. The mitochondrial DNA control region was used due to its high substitution rate, haploid nature, maternal inheritance and absence of recombination. The mtDNA sequencing showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the core distribution of poenskop showed high genetic diversity (h = 0.88, π = 0.01), low genetic differentiation among regions, no spatial structure (ɸST = 0.012, p = 0.208) and no evidence of isolation by distance. The collapsed stock status of poenskop as well as the fact that it is being actively targeted by recreational and commercial fishers suggests that this species requires improved management, with consideration given to its life-history style, residency and poor conservation status. Management recommendations for poenskop, combined with increasing South Africa’s existing MPA network, include the possibility of setting up a closed season (during known spawning periods) as well as the decommercialisation of this species. The techniques used and developed in this study can also be adopted for other overexploited linefish species.

White steenbras Lithognathus lithognathus (Pisces: Sparidae) has been a major target species of numerous fisheries in South Africa, since the late 19th century. Historically, it contributed substantially to annual catches in commercial net fisheries, and became dominant in recreational shore catches in the latter half of the 20th century. However, overexploitation in both sectors resulted in severe declines in abundance. The ultimate collapse of the stock by the end of the last century, and the failure of traditional management measures to protect the species indicate that a new management approach for this species is necessary. The species was identified as a priority for research, management and conservation in a National Linefish Status Report. Despite knowledge on aspects of its biology and life history, little is known about juvenile habitat use patterns, home range dynamics and movement behaviour in estuaries. Similarly, the movement and migration of larger juveniles and adults in the marine environment are poorly understood. Furthermore, there is a complete lack of information on its genetic stock structure. Such information is essential for effective management of a fishery species. This thesis aimed to address the gaps in the understanding of white steenbras movement patterns and genetic stock structure, and provide an assessment of its current conservation status. The study adopted a multidisciplinary approach, incorporating a range of methods and drawing on available information, including published literature, unpublished reports and data from long-term monitoring programmes. Acoustic telemetry, conducted in a range of estuaries, showed high site fidelity, restricted area use, small home ranges relative to the size of the estuary, and a high level of residency within estuaries at the early juvenile life stage. Behaviour within estuaries was dominated by station-keeping, superimposed by a strong diel behaviour, presumably based on feeding and/or predator avoidance, with individuals entering the shallow littoral zone at night to feed, and seeking refuge in the deeper channel areas during the daytime. Conventional dart tagging and recapture data from four ongoing, long-term coastal fish tagging projects, spread throughout the distribution of this species, indicated high levels of residency in the surf zone at the late juvenile and sub-adult life stages. Consequently, juvenile and sub-adult white steenbras are vulnerable to localised depletion, although they can be effectively protected by suitably positioned estuarine protected areas (EPAs) and marine protected areas (MPAs), respectively. It has been hypothesized that adult white steenbras undertake large-scale coastal migrations between summer aggregation areas and winter spawning grounds. The scale of observed coastal movements was correlated with fish size (and age), with larger fish undertaking considerably longer-distance coastal movements than smaller individuals, supporting this hypothesis. Given the migratory behaviour of adults, and indications that limited spawning habitat exists, MPAs designed to protect white steenbras during the adult life stage should encompass all known spawning aggregation sites. The fishery is plagued by problems such as low compliance and low enforcement capacity, and alternative management measures, such as seasonal closure, need to be evaluated. Despite considerable conventional dart tagging effort around the coastline (5 782 fish tagged) with 292 recaptures there remains a lack of empirical evidence of fish migrating long distances (> 600 km) between aggregation and spawning areas. This uncertainty in the level of connectivity among coastal regions was addressed using mitochondrial DNA sequencing and genotyping of microsatellite repeat loci in the nuclear genome, which showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the white steenbras core distribution showed high genetic diversity, low genetic differentiation and no evidence of isolation by distance or localised spawning. Although historically dominant in several fisheries, analysis of long-term commercial and recreational catch data for white steenbras indicated considerable declines and ultimately stock collapse. Improved catch-per-unit-effort in two large MPAs subsequent to closure confirmed that MPAs can be effective for the protection of white steenbras. However, the current MPA network encompasses a low proportion of sandy shoreline, for which white steenbras exhibits an affinity. Many MPAs do not prohibit recreational shore angling, which currently accounts for the greatest proportion of the total annual catch. Furthermore, EPAs within the juvenile distribution protect a negligible proportion of the total available surface area of estuaries – habitat on which white steenbras is wholly dependent. Despite some evidence of recent increases in abundance in estuaries and the surf zone in certain areas, white steenbras meets the criteria for “Endangered” on the IUCN Red List of Threatened Species, and for “Protected species” status on the National Environmental Management: Biodiversity Act of South Africa. The species requires improved management, with consideration for its life-history style, estuarine dependency, surf zone residency, predictable spawning migrations and its poor conservation status. The multidisciplinary approach provides valuable information towards an improved scientific basis for the management of white steenbras and a framework for research that can be adopted for other overexploited, estuarine-associated coastal fishery species.

This thesis investigates the movement behaviour of South African two coastal fish species and evaluates the effectiveness of marine protected areas (MPAs) in their protection and management. Its primary focus is on resolving the movement patterns of roman Chrysoblephus laticeps (Sparidae) in and around the Goukamma and Castle Rock MPAs in the Western Cape province of South Africa. A pilot study of the methodology investigated the movement behaviour of spotted grunter Pomadasys commersonnii (Haemulidae) in the sheltered East Kleinmonde Estuary in the Eastern Cape province. The application of different tagging methods was tested in a controlled tank experiment. Tagged roman were monitored over a 198-day period. Barbed dart, t-bar anchor and Visible Implanted Fluorescent Elastomer (VIFE) tags were compared. Application techniques and underwater visibility of VIFE tags were tested on roman and on fransmadam Boobsoidia inornata in a pilot study. Needles of gauge 25 were found to be optimal for VIFE tag application. Whereas VIFE tagging caused fin rot in fransmadam, it had no negative effect on roman. VIFE tagged fish could be identified by divers from a distance of three metres under ambient light in an observation tank in five metres water depth. There was no significant difference in growth rate between groups of roman with different tags and controls after 198 days. High tag loss rates were experienced for barbed dart and t-bar anchor tags, although barbed dart tags performed better than t-bar anchor tags. Although some of the VIFE marks had deteriorated, all VIFE tagged fish were individually recognised at the end of the study. Conventional dart and VIFE tags are feasible methods to tag roman. However, the high tag loss rate of conventional tags must be taken into account in the design of a tagging study. Previous mark and recapture studies on roman are beset with a number of problems. Poor experimental design and low precision of capture positions resulted in equivocal results of limited value. A tagging experiment was designed to eliminate ambiguity in data interpretation and to produce a dataset that could be used to model roman residency and dispersal. A combination of conventional barbed dart tags and Visible Implanted Fluorescent Elastomer tags was used to tag roman in the Goukamma Marine Protected Area (GMPA) on the temperate South African south coast. Sixty one percent of roman were recaptured within 50 m of the tagging position. A small proportion moved considerable distances of up to four kilometres. The extent of these movements was not dependent on fish size or sex. Data from this experiment and from a previous tagging study in the Tsitsikamma National Park (TNP) were used to model the resident behaviour of roman. The model suggests a probability of 91% (GMPA) and 94% (TNP) of residency within a 10000 m² cell. This result suggests that individual roman will benefit from protection in small MPAs. A different experimental approach was required to investigate the exact home range of this species. Firstly the feasibility of using acoustic telemetry to study the movement of coastal fish in South Africa was investigated. The telemetry equipment comprised two VEMCO V8 transmitters and a VEMCO VR60 receiver linked to a directional hydrophone. A tank experiment was conducted to examine the effects of the transmitter implantation. A tracking experiment was conducted on spotted grunter Pomadasys commersonnii in the East Kleinmonde Estuary. Operated fish recovered quickly and, with respect to swimming behaviour and growth rates, no differences were found between fish with implants and controls. The maximum detection range in the estuary was 400 m. Interference between different transmitter frequencies was negligible. Transmitter location recordings were found to be accurate within five metres. Two fish were tracked over a seven-day period. The fish preferred the lower reaches of the estuary where they made repeated and prolonged use of specific areas. The success of the initial experiments allowed this method to be used to investigate the spatial utilisation and activity patterns of roman Chrysoblephus laticeps. Surgically implanted VEMCO V8, V13 and V16 transmitters were used to track 13 roman inside the Castle Rock MPA in False Bay. Transmitters implanted into C. laticeps in tanks had no apparent effects on growth and physiology. Manual boatand diver-based tracking experiments covered a 17-month period. A VEMCO VRAP radio acoustic positioning system was used over two one-month periods during and after the spawning season of roman. Analysis of data using a 95% fixed kernel algorithm suggests that roman are resident throughout their adult life, occupying home ranges between 1000 and 3000 m². Activity was lower at night. During periods of cold-water upwelling, fish retreated into caves. During the spawning season, females extended their home ranges, possibly to mate with different males. These results confirm that this species is well suited for protection and management with small MPAs. The effect of two MPAs on the South African south coast on the population of C. laticeps was simulated with a spatially explicit individual based model (IBM). Life history parameters determined in recent studies and the effect of fishing on the size of sex change was taken into account. Fish densities and size frequencies were based on recent underwater visual census. The distribution of suitable habitat in the study areas was also incorporated. The results show a rapid recovery of the fish size frequency spectrum and sex ratio to pre-exploitation levels inside both MPAs. Little 'spillover' of fish into the fished areas occurred resulting in negligible improvement of catches. The results suggest that for resident species like roman, even small MPAs offer sufficient protection.