The dynamics of crappie populations in southwestern reservoirs are not well documented. In order for managers to enhance a crappie fishery, they need to understand the factors that control populations. I examined potential limiting factors for black crappie in 4 sequential reservoirs on the Salt River, Arizona. Only in Roosevelt Reservoir, the uppermost reservoir, were crappie relatively abundant. I identified 3 possible limiting factors. Apache, Canyon, and Saguaro reservoirs lacked sufficient spawning substrates. All 4 reservoirs lacked sufficient cover. Finally, the lower 3 reservoirs are less productive during the fall according to chlorophyll a levels than Roosevelt Reservoir. Low productivity may have resulted in fewer zooplankton and possibly a limited forage base for juvenile crappie. Options such as spawning platforms, artificial cover, fertilization, and stocking are discussed as ways to improve the crappie fishery in these reservoirs.

The ecology and behavior of nine species of anemonefishes and ten species of sea anemones were studied at a variety of sites in the region of Madang, Papua New Guinea. More than 95% of the suitable anemones in the region were occupied by anemonefishes. Each species of fish had a distinct pattern of host specificity and population surveys at three replicate reef sites within four locations situated at varying distances from the mainland (nearshore, mid-lagoon, outer barrier, and offshore), indicated that each species of host anemone and anemonefish lived within a particular range of locations. Recruitment was monitored to anemones in natural populations and to anemones that had their resident fishes removed. Significantly more fish recruited to anemones without residents. Each fish species recruited into the host species and locations occupied by their adults. Thus, recruitment had a strong effect on patterns of anemonefish host specificity and distribution, but fish abundance was limited by the availability of anemones. / The host location and association behaviors of laboratory raised anemonefishes were examined. Juvenile anemonefishes that were competent to settle were released in the field at different distances and orientations away from anemones. The fishes were only attracted toward particular species of anemones, and they used chemical cues released from anemones and rheotaxis to locate their hosts. Resident fishes were aggressive toward new recruits and usually prevented them from staying with anemones. Recruiting anemonefishes contacted the tentacles of most anemone species without harm, but in some cases the fishes were stung. Forced contact tests with anemonefish eggs, larvae, juveniles, and adults showed that the fish species tested developed some level of protection from anemones during metamorphosis from a pelagic larva to a benthic juvenile. Forced contact tests with fishes reared in complete isolation from anemones demonstrated that the protection was innate for some species of anemonefishes. However, juvenile fishes still went through acclimation behavior during the initial interaction with an anemone, even if the fishes were innately protected. Immunological studies with polyclonal antibodies to anemone mucus antigens showed that anemonefishes acquire anemone antigens in their mucus coat during their association with anemones. / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5524. / Major Professor: R. N. Mariscal. / Thesis (Ph.D.)--The Florida State University, 1992.

The study establishes the value in recreational use of Florida's saltwater tourist fishery, using exact Hicksian compensating and equivalent variation methods. The Hicksian approach removes the approximating error of Marshall's consumer's surplus measures. The theoretical model underlying the angling experience emphasizes the multi-purpose nature of the tourist trip. It is based upon a Gibbs-type approach in which variable on-site cost proxies market price and travel cost enters the budget constraint. On-site cost and angling success rate are explicitly incorporated into a system of behavioral relations. Some restrictive assumptions found in similar studies are relaxed with composite goods utility. Empirical estimates for aggregated and subgroup angling categories are made with multiple equation models of identified linear and non-linear specifications. There is some evidence that shore anglers might be more and less sensitive to changes in on-site cost and success rate, respectively. Single equation models are also used, but exhibit downward coefficient bias. Results corroborate the findings of previous studies that the market and non-market values of Florida's marine recreational fishery are very large relative to state product and/or commercial sector activity. Inelastic short run price and success rate elasticity is confirmed. Hicksian methods are not shown to be significantly more accurate than most Marshallian ones, except in the case of the direct aggregate user opinion method. Sensitivity analysis offers policy implications supporting a marine tourist fishing license and stock rebuilding schemes, such as bag limits for depleted species. The unrecoverable deadweight burden to society caused by a $10 annual tourist fishing license is less than one percent of the $31 million in direct, adjusted license revenues estimated to be forthcoming annually. / Source: Dissertation Abstracts International, Volume: 45-09, Section: A, page: 2917. / Thesis (Ph.D.)--The Florida State University, 1984.

I analyzed the Seri Exclusive Fishing Zone (SEFZ) in the Gulf of California, to assess its efficiency in solving common fisheries management problems related to open access resources. A review of the major historical changes in the socio-cultural context of marine natural resource use in the region showed the SEFZ has allowed the Seri to successfully keep and improve control of access to the Infiernillo Channel, as well as reduce competition with fishers from Bahia Kino in a region with increasing competition for marine resources. However, the SEFZ showed severe limitations that produced conflicts of variable intensity. The most important were lack of clear geographic limits to SEFZ, clear systems to transfer fishing rights, and rights to defend with armed guards the integrity of their marine territory. The role of Seri and Federal Government authorities in conflict creation and resolution and the perception of the outcomes of these conflicts for Seri and Bahia Kino fishers are analyzed on four recent conflict events. Several potential opportunities to promote co-management of fisheries by the federal government and local fisheries management authorities emerged from the SEFZ. However, none of these opportunities, in the form of informal arrangements, succeeded in creating better relationships between Seri and Bahia Kino communities of fishers. I used the jaiba (Callinectes bellicosus) crab fishery inside the SEFZ to assess dynamics of marine resources under Seri common property ownership. I found that inside the SEFZ fishing effort is controlled, the fishing ban is honored, fishing areas are rotated throughout the season, and no-fishing zones are functional. I used data from jaiba buyers, and extensive catch sampling during two fishing seasons, to determine yearly production in Punta Chueca, as well as average daily catch and other descriptive catch statistics. Jaiba is an important resource in the economy of Punta Chueca, and its local management has been facilitated by the SEFZ to produce a fishery that, to date, appears to be sustainable. However, the long-term viability of this fishery inside the SEFZ is vulnerable to outside harvesting patterns and to political and economic influences over which the Seri have no control.

This dissertation investigates the implication of combining economic and ecological models in an effort to expand our knowledge of the complex problems associated with resource management. The motivation for this research arises from the perceived need to develop a better understanding of how the flow dynamics within a resource affect the efficient management of that resource. Following the introduction, the second chapter experimentally tests the theoretical models of agent behavior in patchy resource environments under both sole-ownership and competitive extraction regimes. In each setting experimental results indicate that subjects over-allocate vessels to regions that possess the greatest rates of emigration within the bioeconomic system relative to the theoretical predictions. This introduces a "spatial externality" because over-harvesting in one region reduces the harvest in the surrounding regions. The third chapter proposes a potential solution to the problems associated with a spatial externality by analyzing the use of marine reserves in the presence of a heterogeneously distributed resource. This is conducted by introducing the presence of biological "hot spots" (areas within a fishery that possess a larger growth potential than the surrounding areas) with spatial rates of migration into the current economic theory. Simulation results indicate that the presence of biological hot spots within a fishery creates an environment within which it is optimal to establish a marine reserve that increases the value of the fishery. The fourth chapter makes use of my earlier experimental and simulation research, which indicate that locational choice and the spatial distribution of effort should affect the management of the fishery. Within this chapter a spatial Heckit model is developed to empirically investigate for the presence of herding behavior among yellowfin sole and Pacific cod fishermen in the Eastern Bering Sea. Econometric results provide support for herding behavior among fishermen within the yellowfin sole fishery. Moreover, fishermen respond to the lagged biomass and spatially weighted biomass signals as significant determinants of locational choice. This results in Lotka-Volterra oscillations in the Pacific cod fishery. In the final chapter of this dissertation, the general findings are concluded and some future avenues of research are discussed.

Species are often composed of discrete breeding units called populations, demes, or stocks. Each stock, while not reproductively isolated from other conspecific populations, may have limited opportunities to interbreed with others due to geographic separation. Allopatric stocks are favored, fortuitously arise, or become extinct, through differential selective pressures (including fishing and disease) acting either locally or throughout the geographic range of a species. Usually, these selection processes result in genetic and morphological dissimilarities between stocks. Whereas changes in the genotype are commonly reflected in the morphology of the individual, shifts in morphology do not always result from alterations of the genotype; morphological change can be induced by environmental factors (phenotypic plasticity). Therefore, it is essential to combine morphological with genetic analyses in studies of wild population identification. The goals of my research were to identify and characterize morphological stocks of Penaeus stylirostris and P. vannamei in the Gulf of California, and to conduct genetic analysis on the identified morphotypes of P. stylirostris to confirm their population structure. Seventy-eight variables were obtained from 417 specimens of P. stylirostris (representative of 21 fishing grounds) and 218 P. vannamei (representing 14 fishing grounds) and analyzed by principal component and canonical variate analyses. Morphometric analysis revealed three distinct regional stocks of P. vannamei and five of P. stylirostris. Genetic structure of P. stylirostris populations was tested from 78 samples (representing six fishing grounds in the Gulf) of male total genomic DNA extracted from frozen shrimp tails. The DNA samples were adjusted in distilled water to a final concentration of 10 ng/mul, and amplified with 20 random 10-mer primers (Operon) on a Perkin Elmer Thermocycler. The PCR RAPD profiles were used to identify between stock genetic differences. The novel adoption of sequencing gels to analyze RAPD profiles, proved useful in demonstrating (significant) genetic differences between specimens from all six fishing grounds. My research demonstrates the importance and applicability of combining morphological and genetic analyses in studies of wild stock identification. The relevance of my findings to the management of the Mexican shrimp fishery and the aquaculture industry are thoroughly discussed.

These studies were begun during the summer of 1994, W2 years after the recognition of Taura Syndrome (TS), a lethal disease of farm-raised Penaeus vannamei in Ecuador of then unknown etiology. Utilizing specific pathogen free (SPF) P. vannamei test shrimp, the combined results of four initial TS bioassays suggested that the disease had an infectious instead of a toxic etiology as originally reported. The hypothesis that TS was virus-caused prompted the application of a shrimp parvovirus (IHHNV) purification protocol, which resulted in the discovery of Taura Syndrome virus (TSV), a previously unrecognized virus that was isolated from TS diseased shrimp tissues. Three serial infectivity studies were performed in which purified cell-free extracts of TSV were injected into SPF P. vannamei test shrimp and the criteria of Rivers' postulates were fulfilled, establishing that TS has a viral etiology. In situ hybridization assays for the detection of TSV resulted in frequent false negative gene probe results. This problem was due to fixative-induced acid hydrolysis of the TSV RNA genome resulting from tissue fixation with Davidson's solution (pH 3.5-4). Development and use of a neutral fixative, R-F (RNA-Friendly) fixative, was shown to prevent this problem. The pathogenesis of TSV lesions was analyzed in experimentally infected, time course sampled SPF P. vannamei. The TSV disease cycle was found to consist of three clinically and histologically distinct overlapping phases; an W7 d acute phase, an W5 d transition phase and a long term cyclic chronic phase of at least 8 months duration. TSV susceptibility studies of two endemic North American (P. setiferus and P. aztecus) and one Asian penaeid species (P. chinensis) showed that P. aztecus and P. chinensis juveniles were susceptible, whereas, P. setiferus appeared refractory to TSV infection. The geographic range of TSV within the Americas was documented based on gene probe and histological findings of archived P. vannamei samples dating from 1992 to 1996. TSV was detectable within P. vannamei submitted from Ecuador when the disease was first recognized (1992) and has since spread into 12 other countries. The causes and effects of the international controversy of a viral versus a toxic etiology for TS are discussed and a solution offered to prevent similar disputes in the future.

I studied the East Pacific green turtle, Chelonia mydas agassizii , at the Bahia de los Angeles foraging grounds of the Gulf of California from July 1995 to October 1999. Entanglement nets were used to capture 153 green turtles among 16 capture sites. Pooled straight carapace length (SCL; mean ± SE) was 75.1 ± 0.79 cm. Though there was no significant variation in mean SCL among years, there was evidence of a difference in mean SCL among capture sites. Most of the population (58%) consisted of immature turtles but did not differ significantly from a 1:1 immature:adult ratio. Pooled adult sex ratio (F:M) was biased toward probable females (2.70:1.00) and differed substantially from a 1:1 ratio. Approximately 5% of the population showed signs of anthropogenic-derived injuries ranging from missing flippers to boat impact scars. I collected gastric lavage samples from 101 green turtles and fecal samples from a subset of 45 turtles. Digestive tract contents were analyzed from seven stranded carcasses. The primary alga recovered in diet samples was Gracilariopsis lemaneiformis. Other major diet items included the green algae Codium sp. and Ova lactuca. Animal matter was found in all sample types. Tube worms (Sabellidae), sponges (Porifera), sea hares (Aplysia vaccaria), and sea pens ( Ptilosarcus undulatus) were the most commonly ingested invertebrates. I studied home range sizes and movements of 23 C. m. agassizii . Mean minimum convex polygon home range area was 1,801 ha. Kernel density estimates (95%) of home range area had a mean of 1,545 ha. Home range length averaged 7,548 m. Mean 24-h vagility was 9,535 m. Diurnal and nocturnal movements were evident. Turtles exhibited a bimodal pattern in which they foraged in nearshore algae pastures during evening and night hours and moved to offshore and/or insular resting sites by midmorning. This study indicates that Bahia de los Angeles is an important foraging and developmental habitat for C. m. agassizii. Management efforts should focus on reducing human disturbance and the use of entanglement nets in the entire bay. In such efforts it is essential that local inhabitants are provided with alternatives that encourage sustainable marine resource use and economic progress.

Recent declines in the availability of large marine shrimp reinvigorated the market for the freshwater prawn Macrobrachium rosenbergii. Simultaneously, pressures to find more lucrative and water efficient crops are increasing in arid regions. The integration of a highly valuable crop such as Macrobrachium with irrigated agriculture could be of benefit to arid land farmers. Using a specific farming region in Arizona as a model of arid land systems, the objectives of my research were to: (1) Determine if the physical conditions for prawn culture occur in Arizona. (2) Investigate the feasibility of inland larvae culture. (3) Raise to maturity and spawn M. rosenbergii. (4) Assess the utility of a new species evaluation protocol. To meet these objectives, I reviewed physical conditions in Central Arizona and compared them to known requirements for culture of M. rosenbergii, developed a model larvae culture method and stocked postlarvae from the larvae culture experiments into ponds where they could grow to maturity and spawn. After spawning, the larvae were collected and the fecundity of the adult females determined. My results suggest M. rosenbergii likely can be cultured seasonally in ponds filled with surface water within the representative region. Constraints to culture include high source water pH, hardness, alkalinity, contaminants and low winter water temperatures. Larvae culture is possible within the representative region. However, successful mass culture will require refinement of techniques used in my study. Constraints to culture include high ambient pH of surface waters, periodic high hardness and alkalinity levels and low winter temperatures. Improved filtration techniques in the incubator and a consistent availability of Artemia for food are also issues of concern. Prawns hatched and grown in Arizona spawned readily, were as fecund as other cultured stocks and produced viable larvae up through stage 2. The protocol I used was appropriate for evaluating a species for aquaculture at a new location. Overall, M. rosenbergii shows potential as a candidate for integration with irrigated agriculture systems within arid farming regions.

Aquaculture has great potential to help supply the nutritional needs of a growing population. To date, however, the benefits that aquaculture can have, have largely been overshadowed by the environmental degradation some segments of the industry have caused. The following body of work describes my efforts to help reduce the environmental impacts of aquaculture. By integrating aquaculture production into traditional agriculture, the impact of farming on already limited water resources and the reliance on chemical fertilizers can be reduced. Recent expansion of the aquaculture industry in Arizona has made it possible to study the integration of olive groves with marine shrimp culture. In chapter 3, I describe the characterization and evaluation of the effluent from an inland, low-salinity shrimp farm as a potential source of irrigation water. I found that 0.41 kg of ammonia-nitrogen, 0.698 kg of nitrite-nitrogen, 8.7 kg of nitrate-nitrogen and 0.93 kg of total phosphorus (TP) were made available as fertilizer each day in the effluent water. Based on the results of this first study, I decided to conduct a farm trial to quantify the effects of these shrimp farm effluents on olive trees. This work is described in chapter 4. Trees in all treatment groups grew an average of 40.1 cm over the four month study period. While growth of trees irrigated with shrimp farm effluent did not improve in respect to the other treatments, our results do indicate that irrigating with low-salinity water had no noticeable negative effects. Chapter 5 describes work conducted in Idaho, as part of a larger study aimed at reducing the effluent loads of phosphorus (P) from high density, flow-through aquaculture facilities. Research steps were taken to establish a relationship between TP and the carbon 12/13 isotope ratio (δ¹³C) and/or the nitrogen 14/15 isotope ratio (δ¹⁵N). Our findings suggest that both δ¹⁵N and δ¹³C are good better proxies for P, after correcting for P retention. A linear regression of %P (corrected) on δ¹³C and δ¹⁵N resulted in R2 values of 0.843 and 0.8622, respectively. This suggests that by tracking δ¹⁵N and/or δ¹³C through a high-density, flow-through aquaculture facility over time I will be able to determine the residence time of P with a high degree of accuracy.