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From 1970 to the present 10 artificial reef sites have been developed in coastal waters of the Ligurian Sea, Italy. They range from Ventimiglia, in the west, to La Spezia, in the east, with the largest and best known reef complex being located in the Gulf of Genoa at Loano and consisting of 2,745 m3, about 5,200 t of material and covering a surface of 350 ha. Design and construction practices have advanced from an initial, unsuccessful effort that used automobile bodies (now banned) to current use of custom-designed concrete modules deployed systematically. Funding for reef construction has come since 1983. The earliest aim of reefs was as a physical barrier to protect habitats against illegal otter trawl fishing. Newer objectives include habitat restoration, enhancement of biodiversity and fishing catch, and research to test materials and designs for physical and ecological performance. Reefs also functions as environmental observation stations, with the invasive species Caulerpa taxifolia (Vahl) C. Agardh, being recorded on the reef at Alassio. For some Artificial Reefs (Ars), benthic organisms and fishes, settlement, biomass and development of community are recorded. In Loano AR, immersed in 1986, more than 150 algae species are recorded, more than 200 benthic animal species and 78 species (87 taxa) of fishes. Fifty-six species (61 taxa) of fishes are recorded by visual census, the others are caught only by trammel net and long line. Trammel catches at Loano are on average about 2.32 kg/100 m net. Comparisons among ARs reveal that age of the reef, location and presence of seagrass meadows are crucial for success. An indication of functional equivalence between ARs and natural rocky reefs is seen if both fish and sessile macrobenthos are compared. After 34 years of investigation a database comprising at least one hundred scientific articles based on research programs of up to 15 years, and other unpublished reports, provides information to guide future planning of reefs. On the basis of acquired experience, some management advice is suggested and the best design for the basic module in the Ligurian sea is described. The role of ARs, providing protection of coastal environment against the illegal otter trawling, nursery, microhabitat and food supply, while increasing biodiversity, biomass of benthos and fishes, and facilities for ecotourism, is outlined. [ABSTRACT FROM AUTHOR]

The artificial reef (AR) complex of the Algarve (Southern Portugal), deployed for the purpose of restoring and enhancing fisheries resources, is currently the largest structure of its kind in Europe, extending for over 43.5 km2. Such a structure can be expected to have had both positive and negative impacts. To evaluate the overall perception of the effects of deployment, a survey of stakeholders' opinions was undertaken based on a set of questions addressing various dimensions (environmental, social, and economic). The survey covered 44 key-stakeholder representatives distributed in six groups: commercial fishermen associations, anglers associations and clubs, diving schools and clubs, fisheries and environmental administrators, natural and social scientists, and local council representatives in the fisheries and/or environmental sectors. The opinions of stakeholders were measured using summated rating scales. The results obtained reflect the most important issues be impacted and the possibility of using them as indicators of relative success or failure. From a total of 12 factor-sets of impacts, the results showed that in general the environmentally related were the ones having had the most positive results. The overall perception of the environmental factor-sets specified as the ‘deployment area use' revealed that the artificial reefs were an incentive to users and that the structures were perceived as a satisfactory tool to support the fishery and its management. In both cases divers were the strongest supporters. A closer look at the results presented in the form of an AMOEBA plot showed that there were other factor-sets perceived as impacting positively in other dimensions. Such examples are the factor-sets ‘opinion' and ‘production and benefits' lying respectively in the social and economic dimensions. The latter factor-set was even the only one having the support of five out of six stakeholder-types. As expected, in general different stakeholder-types take somewhat different positions and attitudes towards AR impacts: usually scientists are the most optimistic, whereas fishermen take the most sceptic view. [ABSTRACT FROM AUTHOR]

This study was carried out on the "Faro/Ancão" artificial reef (AR), located off Faro, deployed in May 2003. We aimed to characterise early macrobenthic community colonisation of two concrete AR groups located at different depths (16 m and 20 m depth) and to test the effect of reef structure on these communities. The non-colonial organisms were counted; barnacles and colonial species were quantified using biomass. Multivariate analyses indicated that early macrobenthic communities (6 months of immersion) were affected by depth, and that barnacles and colonial species were also affected by reef structure. Univariate analyses showed that the biomass of barnacles and colonial species was significantly different among reefs and layers of modules. Both AR groups were characterised by the species Balanus amphitrite, Gregariella subclavata, Musculus cf. subpictus, Paleanotus cf. bellis and Syllidia armata. Jassa marmorata and Bugula neritina were characteristic species at 16 m depth, particularly on the AR Upper layer of modules, whereas Anomia ephippium was particularly common at 20 m, especially on the Lower layer of modules. [ABSTRACT FROM AUTHOR]

Derelict ships are commonly deployed as artificial reefs in the United States, mainly for recreational fishers and divers. Despite their popularity, few studies have rigorously examined fish assemblages on these structures and compared them to natural reefs. Six vessel-reefs off the coast of southeast Florida were censused quarterly (two ships per month) to characterize their associated fish assemblages. SCUBA divers used a nondestructive point-count method to visually assess the fish assemblages over 13- and 12-month intervals (March 2000 to March 2001 and March 2002 to February 2003). During the same intervals, fish assemblages at neighboring natural reefs were also censused. A total of 114,252 fishes of 177 species was counted on natural and vessel-reefs combined. Mean fish abundance and biomass were significantly greater on vessel-reefs in comparison to surrounding natural reef areas. Haemulidae was the most abundant family on vessel-reefs, where it represented 46% of total fish abundance. The most abundant family on natural reefs was Labridae, where it accounted for 24% of total fish abundance. Mean species richness was significantly greater on vessel-reefs than neighboring natural reefs and also differed among vessel-reefs. Both mean fish abundance and mean species richness were not significantly different between natural reefs neighboring vessel-reefs and natural reefs with no artificial structures nearby. This suggests the vessel-reefs are not, in general, attracting fish away from neighboring natural reefs in our area. Additionally, economically important fish species seem to prefer vessel-reefs, as there was a greater abundance of these species on vessel-reefs than surrounding natural reef areas. Fish assemblage structure on natural versus artificial reefs exhibited a low similarity (25.8%). Although no one species was responsible for more than 6% of the total dissimilarity, fish assemblage trophic structure differed strikingly between the two reef types. Planktivores dominated on vessel-reefs, accounting for 54% of the total abundance. Conversely, planktivores only made up 27% of total abundance on natural reefs. The results of this study indicate vessel-reef fish assemblages are unique and that these fishes may be utilizing food resources and habitat characteristics not accessible from or found at natural reefs in our area. Production may also be occurring at vessel-reefs as the attraction of fish species from nearby natural reefs seems to be minimal. [ABSTRACT FROM AUTHOR]

Artificial habitats in marine ecosystems are employed on a limited basis to restore degraded natural habitats and fisheries, and more extensively for a broader variety of purposes including biological conservation and enhancement as well as social and economic development. Included in the aims of human-made habitats classified as artificial reefs are: Aquaculture/marine ranching; promotion of biodiversity; mitigation of environmental damage; enhancement of recreational scuba diving; eco-tourism development; expansion of recreational fishing; artisanal and commercial fisheries production; protection of benthic habitats against illegal trawling; and research. Structures often are fabricated according to anticipated physical influences or life history requirements of individual species. For example, many of the world's largest reefs have been deployed as part of a national fisheries program in Japan, where large steel and concrete frameworks have been carefully designed to withstand strong ocean currents. In addition, the differing ecological needs of porgy and sea bass for shelter guided the design of the Box Reef in Korea as a device to enhance productivity of marine ranching. The effect of these and other structures on fisheries catch is positive. But caution must be exercised to avoid using reefs simply as fishing devices to heavily exploit species attracted to them. No worldwide database for artificial habitats exists. The challenge to any ecological restoration effort is to define the condition or possibly even the historic baseline to which the system will be restored; in other words, to answer the question: "Restoration to what?" Examples of aquatic ecosystem restoration from Hong Kong (fisheries), the Pacific Ocean (kelp beds), Chesapeake Bay (oysters) and the Atlantic Ocean (coral reefs) are discussed. The degree to which these four situations consider or can approach a baseline is indicated and compared (e.g., four plants per 100 m2 are proposed in one project). Measurement of performance is a key factor in restoration planning. These situations also are considered for the ecosystem and fishery contexts in which they are conducted. All use ecological data as a basis for physical design of restoration structures. The use of experimental, pilot and modeling practices is indicated. A context for the young field of marine restoration is provided by reviewing major factors in ecosystem degradation, such as high stress on 70% of commercially valuable fishes worldwide. Examples of habitat disruption include an extensive hypoxic/anoxic zone in the Gulf of Mexico and nutrient and contaminant burdens in the North Sea. Principles of ecological restoration are summarized, from planning through to evaluation. Alternate approaches to facilitate ecological recovery include land-use and ecosystem management and determining levels of human population, consumption and pollution. [ABSTRACT FROM AUTHOR]

The opening of the Suez Canal resulted in the introduction of Indo-Pacific organisms (Lessepsian) to the eastern Mediterranean. Available information on the Levantine ichthyofauna concerns mainly necto-benthic species, while pelagic ones remain mostly uncharacterized. This paper presents a preliminary assessment of biodiversity and its temporal changes on the Lebanese coast (eastern Mediterranean) using species composition and abundance of pelagic communities as indicators. For this purpose, a total of 11,192 fishes, representing 32 species and 19 families were collected with purse seines. Lessepsian species represented 40.9% of the species number in the purse-seine catches but only 0.48% in abundance of individuals and 1.57% in biomass. The families most represented in terms of abundance were the Clupeidae (49.28%), the Engraulidae (41.69%) and the Scombridae (7.01%); in terms of biomass these families represented 56.76, 22.04 and 9.72%, respectively. Abundance and biomass exhibited clear temporal fluctuations with Sardina pilchardus and Scomber japonicus dominating the catches between May and June, and then replaced by Sardinella aurita in July and Engraulis encrasicolus in August. The highest values of species richness (12 species) and diversity indices (H′ = 1.37; D = 0.71) were recorded in the last two weeks of June while the lowest values (5 species, H′ = 0.26; D = 0.11) were recorded in early August. While Lessepsian fishes represented a minor part in terms of landings, they contributed considerably to the diversity of pelagic fish assemblages in Lebanese waters. [ABSTRACT FROM AUTHOR]

In this paper, species diversity of demersal fish communities was analysed over an area covering about 45,000 km2 of the Italian side of the Strait of Sicily (central Mediterranean). Fish abundance data come from a 10-year series (1994-2003) of experimental bottom trawl surveys carried out within the framework of the international program MEDITS. A simple GIS-based method was proposed to identify areas supporting high or low values of diversity and evaluate their temporal stability. A well-defined spatio-temporal pattern in diversity emerged from the analysis, with some areas of great ecological relevance being identified. Importantly, the greatest diversity within the fish communities was consistently seen at the offshore bank on the western part of the south Sicilian shelf (Adventure Bank). The site also supports high total biomass of demersal resources and shows the presence of species of great concern to fisheries. Results suggest that Adventure Bank represents a priority site for investigating the possibility of innovative management of marine ecosystems and demersal fisheries in offshore zones. [ABSTRACT FROM AUTHOR]

The relationships between the concentration of water nutrients and the biomass of benthic invertebrate feeding guilds were examined at 46 sites in the northern Baltic Sea during 1993-2003. We analysed whether and how degree of exposure, presence of fronts, salinity, hypoxia, nutrient concentrations, depth, sediment type and structure of invertebrate communities contributed to these relationships. In general macrozoobenthos did not respond to the changing nutrient concentrations in the areas that were regularly impacted by fronts (river estuaries, bank slopes, straits). Macrobenthic species diversity, depth, 11-year average of nutrient concentration and sediment type explained best how strong the nutrient-invertebrate relationships were. The deposit feeders, that inhabited more diverse communities, were less sensitive to the increased concentration of nutrients than those in less diverse communities. On the other hand, the sensitivity of suspension feeders to rising nutrient load increased with benthic diversity. The response of macrozoobenthos to nitrogen level decreased with increasing depth. Our data did not support the hypothesis that there was a significant difference in the occurrence of nutrient-invertebrate relationships between hypoxic and normoxic conditions. The probability of finding negative nutrient-invertebrate relationships increased with depth. The results pointed to nitrogen limitation in the coarse and fine sediments and phosphorus limitation in the mixed sediments. Increased nitrogen values strengthened the response of suspension feeders to the concentration of phosphorus. Increasing phosphorus level dampened the relationships between benthic functions and concentration of phosphorus. This study confirmed that depth and sediment type were the best regularly monitored abiotic variables that could be used to determine the type areas within the northern Baltic Sea in sensu the European Community Water Framework Directive. As the nutrient-invertebrate relationships were significantly modified by macrobenthic diversity, the environmental classification should incorporate specific biological measures such as benthic diversity in order to better describe the quality status of the water body. [ABSTRACT FROM AUTHOR]

Several species of bivalves coexist at the lower intertidal of large tidal flats located in the enclosed or inland coast of the northern area of the Nord-Patagonic archipelagos on the Chilean coast (ca. 40-42°S): Tagelus dombeii (Lamarck), Mulinia edulis (King & Broderip), Venus antiqua King & Broderip, Semele solida (Gray), Gari solida (Gray) and Diplodonta insconspicua Philippi. To explore possible spatial variation in the community structure of the macroinfauna inhabiting sediments with different assemblages of these bivalves, seasonal sampling was carried out during 2003-2004 at two tidal flats of that area. Higher species richness and specimen densities of the macroinfauna occurred in sediments with the higher densities of bivalves, especially in sediments where the deep burrower T. dombeii reaches its greatest abundances. Our results suggest that, apart from presence of bivalves, the burrowing depth of these organisms is also important in promoting the abundance of macroinfauna. Our results are in contrast with earlier conceptualizations for community organization of the soft bottom macroinfauna inhabiting intertidal flats, related to biological interactions occurring among different phyletic groups, such as that arguing that suspension feeding bivalves (such as T. dombeii and V. antiqua) will negatively affect the recruitment of species with planktonic larvae, by filtering them before they become established in the substrate. Thus, it is concluded that beneficial effects of bivalve bioturbation overcome that negative effects on the macroinfauna, although detrimental effects may well occur at bivalve densities higher than those studied here. [ABSTRACT FROM AUTHOR]

The sea urchin Paracentrotus lividus (Lamarck) (Echinodermata: Echinoidea) is an Atlanto-Mediterranean species abundant in the littoral zone, where it occurs in the sublittoral down to 20 m. The aim of our work is to investigate the genetic patterns of P. lividus along the South Tyrrhenian coasts. Five specimens were collected in six localities, from the Gulf of Naples and the Cilento coast. The nuclear rDNA ITS2 spacer and the two mitochondrial genes 16S and COI were used for the analysis. The three markers utilised did not show any structure among populations from the Gulf of Naples. All populations appear to be polyphyletic, with Cilento samples more differentiated from the others. This suggests the existence of phylogeographic structure at larger geographic scale. Absence of genetic structure has been interpreted taking into consideration theoretical dispersal of the planktotrophic larvae, which can survive for 4-8 weeks before settlement, marine current patterns and persistence of the species in the area. [ABSTRACT FROM AUTHOR]

Phytoplankton succession and sinking rates were studied from January to December 2003 at a coastal station in the Gulf of Trieste (northern Adriatic Sea), 200 m offshore, in a relatively undisturbed area. A conical sediment trap, moored at 15 m depth (water depth 17 m), was used. The hypothesis if the presence of benthic and epiphytic diatoms can lead to an overestimation of the vertical fluxes was tested. To evaluate primary and secondary sedimentation contributions, planktonic, benthic and epiphytic diatoms were distinguished. Benthic species abundance varied throughout the year and it was related to resuspension that strongly influenced sinking rates. All over the year, diatoms were the prevailing class in the trap material accounting for 75.32% of the settled cells, while flagellates represented 24.11%. Dinophyceae and resting cells constituted minor components, accounting for 0.43% and 0.14%, respectively. The gross sedimentation rates ranged from 0.006 × 108 cell m−2 d−1 in the second week of May to 6.30 × 108 cell m−2 d−1 in the third week of January with a mean annual value of 1.09 ± 1.43 × 108 cell m−2 d−1. To the primary sedimentation rate Pseudo-nitzschia seriata of the group "Nitzschia seriata complex" contributed for 49.77% followed by Chaetoceros spp. (23.88%). The major contributor to the secondary sedimentation rate was the diatom Paralia sulcata, accounting for 24.76%. Epiphytic diatoms contributed for 11.19% and 12.27% on annual average gross abundance and biomass, respectively, reaching even 72.04% of gross abundance and 56.06% of gross biomass in the second week of August. The correlation between temperature and the logarithm of the epiphytic biomass was statistically significant, with r = 0.66 and P < 0.001. Both in the cluster analysis and in the PCA four main groups were formed, where benthic and epiphytic species were separately gathered. Planktonic, benthic and epiphytic forms accounted for 50.78%, 36.95% and 12.27%, respectively, calculated on the annual average biomass. Therefore, vertical fluxes can be overestimated of 50% or more if benthic and epiphytic species are not rejected. [ABSTRACT FROM AUTHOR]

Recently a new index has been proposed for the evaluation of biodiversity: taxonomic distinctness. One of the positive features of this index is that it is neither sampling-effort nor sample-size dependent. Until now, its application has been limited to the assessment of zoobenthos and fish biodiversity. The main objective of this paper was to test the applicability of this index to the macroalgal flora of the Gulf of Trieste (Northern Adriatic Sea). For this purpose the flora recently censused in this area was compared with a checklist of the entire region compiled from the literature. Two indices were mainly used for this study: average taxonomic distinctness based on presence/absence data (AvTD), and variation in taxonomic distinctness (VarTD). Their relationship with species richness was also assessed. The distinctness was compared with statistically significant limits estimated using randomisation tests made on the local master species list. On the same data set multivariate analysis based on a taxonomic similarity index was performed, and a 2nd stage MDS was used to compare results at four taxonomic levels. The results confirmed that statistical over-threshold situations can be highlighted only by one index (AvTD or VarTD) or only by their relationship (AvTD vs VarTD) and not necessarily at the same time by both indices and their relationship. While the average distinctness (AvTD) did not show values significantly different from the expected ones, the variation (VarTD) in one site showed values significantly exceeding confidence limits. This situation has already been described for zoobenthic communities and explained as a consequence of a decrease in habitat diversity. In this case it might be the result of the reduced presence of hard substrata suitable for macroalgal colonisation. The joint analysis of both parameters (AvTD vs VarTD) revealed one site exceeding the 95% confidence limit, which was not identified by analysing only one parameter at a time. This significant over-threshold pattern in the relationship of the distinctness indices could be explained by a relative increase of Rhodophyceae, attributable to the intensive grazing of the sea urchins at this site. The analysis of taxonomic distinctness indices at each site compared with the 95% probability funnels or ellipses derived from the regional species pool gave results consistent with the ones obtained using multivariate analysis. The results of this study suggest that the method may have more general validity. [ABSTRACT FROM AUTHOR]

Monitoring the extension of seagrass meadows over time is of primary importance for the surveillance of marine coastal biodiversity. Here, we analyse the evolution of the meadow of Cymodocea nodosa in the Gulf of Tigullio, a coastal tract of naturalistic interest but subjected to high anthropogenic pressure. Historical maps at a scale 1:25,000 of C. nodosa meadow drawn in 1986, 1991 and 2001 were processed with GIS (Geographical Information System), using overlay vector methods. Diachronic analyses allowed the measurements of temporal changes, in term of percentage gain or loss of meadow extension, through concordance and discordance maps. A general increase in the extension of the meadow from 1986 to 1991 was evidenced, but the disparity of mapping methods (SCUBA diving in 1986, Side Scan Sonar in 1991) in the two surveys imposes caution when interpreting this result. On the other hand, the comparison of 1991 and 2001 maps, both derived from Side Scan Sonar surveys, showed a regression of the meadow of about 60% in the northern area, and modifications in the upper and lower limits of the meadow due to the impact of coastal works. C. nodosa meadow showed the only enlargement in front of the mouth of the Entella River, due to the increase in nutrient contents for rainfall in the period 1988-1994. The overall analysis evidenced a net decrease in seagrass meadow extension, an early warning of risk for marine coastal biodiversity in the Gulf of Tigullio. [ABSTRACT FROM AUTHOR]

The Black Sea ecosystem and diversity underwent dramatic adverse changes during the 1960s and, especially, 1970s and 1980s of the last century. Anthropogenically-induced eutrophication increased through greater biogenic flow, dumping and pollutant discharge, in turn causing red tides, fish kills and oxygen depletion over the northwestern shelf. Anthropogenic pressures, associated with the economic situation of the Black Sea countries, has decreased during the last decade, allowing some improvement in the state and biodiversity of the ecosystem. The abundances of several native species have increased. However, mediterranization—the invasion by species from the adjacent basin and beyond—has continued. The conclusion is grounded, that biodiversity is not only inter- and intra-species diversity but also spatial-temporal variability, abundance and productivity dynamics, differences of the metabolic strategies providing sustainable existence in the changing environment. Biodiversity at the intraspecies level expresses itself in spatial and temporal variations of the Black Sea biota. It has been shown, that preservation of the Black Sea ecosystem's biodiversity must be based on the measures which should be undertaken in national and social spheres, and be directed to the recreation, stabilization and conservation of this unique sea basin. Measures must be implemented nationally to conserve, stabilize or recreate the ecosystem biodiversity of this unique sea basin. [ABSTRACT FROM AUTHOR]

Present-day Mediterranean marine biodiversity is undergoing rapid alteration. Because of the increased occurrence of warm-water biota, it has been said that the Mediterranean is under a process of ‘tropicalization'. This paper analyses the main patterns of the Mediterranean Sea tropicalization and considers briefly its extent and consequences. As happened during previous interglacial phases of the Quaternary, Atlantic water, entering via the Straits of Gibraltar, carries into the Mediterranean species that are prevalently of (sub)tropical affinity. On the other side of the basin, Red Sea species penetrate through the Suez Canal, a phenomenon called lessepsian migration from the name of F. de Lesseps, the French engineer who promoted the cutting of the Canal. Also the many exotic species introduced by humans voluntarily or involuntarily are nearly always typical of warm waters. Climate change combines with Atlantic influx, lessepsian migration and the introduction of exotic species by humans to the establishment of tropical marine biota in the Mediterranean Sea. Present-day warming ultimately favours the spread of warm-water species through direct and indirect effects, and especially by changing water circulation. It is impossible at present to foresee to what extent the exuberance of warm-water species will affect the trophic web and the functioning of marine ecosystems in the Mediterranean Sea of tomorrow. While Mediterranean Sea communities are modifying their pattern of species composition, they do not seem to be acquiring a more marked tropical physiognomy: Mediterranean coastal marine ecosystems are still dominated by fron-dose algae (even if the species that are gaining ascendancy are of tropical origin) and not by corals as is normal in tropical seas. [ABSTRACT FROM AUTHOR]

Muskellunge, Esox masquinongy, were first introduced to Nebraska waters in 1958. By 1967 anglers had caught the first muskellunge from Nebraska waters. Hybrid muskellunge, Esox masquinongy × E. lucius, culture and stocking started in 1976. Harvest regulations for muskellunge and hybrid muskellunge were first established in 1977 with a daily bag limit of one muskellunge or hybrid muskellunge of at least 762 mm (30 inches) in length. In 2000 the minimum length limit for muskellunge and hybrid muskellunge was increased to 1016 mm (40 inches). Hybrid muskellunge have been phased out, none have been stocked in Nebraska waters since 2003. Since 1998 muskellunge fingerlings have been held in Nebraska hatcheries until age-1 before stocking. Yearling muskellunge are raised on minnows and other small fish in Nebraska hatcheries and stocking success apparently is very good. Management and research of Nebraska's muskellunge and hybrid muskellunge fisheries has been limited to routine sampling that has documented the presence of those fish in waters where they were stocked. Fishable populations of muskellunge can now be found in nine Nebraska waters across the state, but most Nebraska anglers are relatively uneducated in fishing techniques for muskellunge, identification, and proper handling. [ABSTRACT FROM AUTHOR]

Minnesota has established a successful muskellunge, Esox masquinongy, stocking program as a result of a series of research studies that enabled area fisheries managers to make informed management decisions. The previous propagation and stocking program (pre-1982) reared muskellunge progeny from Shoepack Lake near the Minnesota-Ontario border, but these fish were not attaining trophy size. Protein electrophoresis showed there were two different muskellunge strains in the state. A controlled study was conducted on progeny from natural muskellunge populations from Leech and Shoepack lakes. Fish from these populations, together, were used to stock two other Minnesota lakes, and their growth rates, age of maturity, and maximum size attained were compared. Leech Lake muskellunge grew faster and attained a larger maximum size than the Shoepack Lake strain. As a result, a new stocking program based on the Leech Lake strain was developed. Because it was difficult to collect Leech Lake gametes, the Minnesota Department of Natural Resources created seven brood stock lakes using Leech Lake progeny. As a result of combining genetic considerations, new research on spawning sites, more restrictive harvest regulations, and catch-and-release fishing, anglers' catch of trophy-sized muskellunge in Minnesota has increased. [ABSTRACT FROM AUTHOR]

In 1995, a 10-year strategic plan for muskellunge program management in Missouri was developed by the Missouri Department of Conservation. Our mission was to efficiently produce and manage muskellunge in order to provide high-quality angling opportunities in suitable, well-distributed lakes throughout the state. The first goal was to increase the number and improve the distribution of muskellunge fisheries in small lakes. In 1995, our three existing muskellunge fisheries were in west central, northwest, and north Missouri. Six additional lakes were stocked with muskellunge from 1995 to 2001 in southeast, northeast, southwest, and central Missouri, plus the St. Louis area. The second goal was to maintain density and size structure of muskellunge populations commensurate with muskellunge angler expectations. Our objective was for muskellunge anglers to catch a muskellunge at least 91 cm (36 in.) in 20-40 h of angling. The Show-Me Muskie Project, a volunteer angler diary program, was initiated in 1996 to help evaluate this objective. The third goal was to inform Missouri anglers about increased opportunities for high-quality muskellunge fishing. We developed a muskellunge web page, created a release poster, updated our muskellunge brochure, published magazine articles, and mailed biannual letters to our Show-Me Muskie Project cooperators. [ABSTRACT FROM AUTHOR]

Growth and ultimate size can provide important population insights and a sound biological basis for setting length limits, which can be the best single regulation for preventing overexploitation of muskellunge (Esox masquinongy) populations. A system was developed, using cleithral age and total length at age confidence limits (CL) data, to determine reproductive and growth potential (ultimate size) for calculating and setting increased size limits based on minimum reproductive size (upper 99% CL at age at first maturity + 2 year) and minimum ultimate size (MUS) calculated from the lower 99% CL—minimum ultimate size limit (MUSL). MUS also provides a trophy standard and an index of relative size for comparing trophy potential of individuals within and among populations. Guidelines are provided for determining minimum sample size (mean ± 95% confidence interval = 12 ± 4) and minimum age (8-10 ± 2.0 year) required to produce valid von Bertalanffy growth trajectories. MUS, MUSL, and trophy standards for both length and estimated weight are provided for female and male muskellunge from 14 Ontario sources. Mean MUS, or trophy standard, for females was 115 ± 10.3 cm (MUSL range 75-135) and 11.1 ± 2.6 kg (2.5-17.5) and for males was 95 ± 7.5 cm (66-110) and 6.1 ± 1.3 kg (1.9-9.2). These indices can precisely define growth and growth potential for muskellunge populations and individuals and can be used to better manage and maintain or improve the quality of muskellunge populations and fisheries. [ABSTRACT FROM AUTHOR]

Use of live bait for angling of muskellunge, Esox masquinongy, is popular in Wisconsin. A traditional method utilizes a large hook through the bait fish's snout, which requires the muskellunge to swallow the bait prior to hook set. Adult muskellunge (>76 cm; 30 in) were held in lined hatchery ponds and caught while fishing with live bait on 10/0 size single hooks. The leader was cut and the muskellunge was released when hooked in the stomach. Survival was monitored for up to 1 year. No immediate (<24 h) mortality occurred. However, 22% of hooked muskellunge died within 50 days and 83% died within 1 year. Necropsies revealed extensive trauma to the stomach and other organs from hooks, along with systemic bacterial infections. Highest mortality on both hooked and control fish occurred over winter through spring. This peak mortality may be associated with natural stressors that occur during the spring spawning period. Mortality rates observed in this study are considered unacceptable for trophy management of muskellunge. Although use of live bait for muskellunge is traditional in Wisconsin, terminal tackle such as quick-strike rigs that hook fish in the mouth or buccal cavity should enhance the chances a released muskellunge will survive. [ABSTRACT FROM AUTHOR]

The muskellunge, Esox masquinongy, fishery in the St Lawrence River is believed to have declined significantly from historical levels and reached critically low levels during the 1970s. Over-exploitation caused by liberal angling regulations, and loss and alteration of critical spawning and nursery habitat probably contributed to this decline. In 1980, a St Lawrence River Muskellunge Management Work Group comprising resource managers and several advisors, including E.J. Crossman, to whom this symposium is dedicated, was created to address research and management needs. A trophy muskellunge management strategy was implemented including more restrictive harvest regulations, public education promoting "catch and release", and protection of spawning and nursery habitats. Age and growth information obtained from cleithra analysis indicated the need for increased size limits to adequately protect spawning stocks. Research efforts have developed a biological information base and monitoring tools to guide management decisions and evaluate responses. Over 100 spawning and nursery locations have been identified in US and Canadian waters leading to improved protection of critical habitats. An angler diary program shows a decline in the number of fish being harvested and a local muskellunge release award program implemented in 1987 has logged over 1000 releases of fish at least 44″ in length. Adult muskellunge monitoring in eleven spawning areas revealed an increase in mean total length of over 63 mm (>2.5 inches) after the regulation changes. Monitoring of age-0 muskellunge by use of seining surveys (1997-2005) indicates consistent reproductive success with the potential for several strong year-classes. Improvements in the muskellunge population and fishery are attributed to the progressive management action and a united community response. [ABSTRACT FROM AUTHOR]

We examined Minnesota's muskellunge, Esox masquinongy, populations using various data sets including spring trap net assessments and angler diary surveys. We confronted a potentially problematic data set that had a large number of zero catches by fitting logistic models to the presence/absence data set and linear models to the subset of data that included catches with one fish or more. Currently, 105 lakes have been identified as muskellunge waters, of which 61 lakes have been created and maintained by stocking. Although the proportion of successful anglers has increased over time, catch rates have remained the same. It appears from analysis of trap net catches that the abundance of 102 cm (40 in) and larger muskellunge has been increasing over time. Both trap net and angler data provide some indications that size of muskellunge caught has also increased over time. Angler-harvested muskellunge averaged 11 years of age and 115 cm (45 in) total length. For Minnesota waters, muskellunge ultimate length averaged 134 cm (53 in) for females and 119 cm (47 in) for males. All evidence indicates a successful management program. [ABSTRACT FROM AUTHOR]

Identification and protection of critical spawning habitat for muskellunge Esox masquinongy and northern pike Esox lucius is important for preserving the reproductive potential of both species. In this study, we implanted miniature radio transmitters through the oviduct into the egg masses of female muskellunge and northern pike just prior to spawning. This non-surgical procedure was a novel approach for identifying spawning sites when transmitters were expelled with the eggs during egg deposition. Preliminary studies in three lakes showed that muskellunge and northern pike deposited many of the transmitters in likely spawning habitat. An inability to find eggs limited our validation of this method, but nevertheless, a relatively high proportion (70%) of northern pike larger than 690 mm (27.2 inches) expelled transmitters in a previously known spawning area in Willow Lake, Minnesota. Shoreline vegetation in that area consisted primarily of sedges Carex spp., and the adjacent water was shallow with substrate consisting of large mats of water bulrush Scirpus subterminalis. A lower proportion (50%) of muskellunge expelled transmitters in Elk Lake, Minnesota. Water depth at likely spawning sites averaged 1.1 m (3.6 feet) and vegetative cover was variable, but Chara spp. was common to most sites. In Moose Lake, Minnesota, containing sympatric populations of muskellunge and northern pike, 60% of muskellunge and 90% of pike expelled transmitters. Chara spp. beds were the predominant substrate where transmitters were expelled in Moose Lake, but the two species deposited transmitters on deepwater bars (3.7-5.2 m) in addition to shallow near-shore habitat. These results suggest more flexibility in depths used for spawning than typically reported for muskellunge and northern pike. [ABSTRACT FROM AUTHOR]

Genetic differences among muskellunge Esox masquinongy populations are related to residence in major river drainages, suggesting the existence of divergent stocks. By use of radio-telemetry we compared different seasonal and diel temperature selection in a southern Illinois reservoir for three geographically and genetically distinct stocks of age-2 muskellunge from throughout the latitudinal range of the species. Muskellunge from the Upper Mississippi River drainage were represented by the Leech Lake, Minnesota, population and the Ohio River drainage was represented by the Cave Run Lake, Kentucky, population. Progeny from North Spring Lake, Illinois, an interstock, or mixed-origin stock, were also evaluated. No differences in temperature selection were observed among stocks of juvenile muskellunge across seasons or diel periods. The seasonal mean temperatures of the water varied significantly—spring 21.7°C, summer 28.4°C, and fall 14.8°C, with an overall average temperature of 24.1°C, in agreement with previously published values obtained in laboratory trials. This lack of different temperature-selection patterns among stocks is in contrast with other life-history characteristics, for example growth, metabolism, and conversion efficiency, which have been shown to differ among populations and stocks. [ABSTRACT FROM AUTHOR]

Reported improvements in the muskellunge angling fishery on Lake of the Woods, Ontario over the last two decades have paralleled an increase in the practice of catch and release angling, and an increase in minimum size regulations for this species. The overall status of muskellunge populations in this large, complex lake has proven difficult to monitor using standard assessment methods. A volunteer muskellunge angler diary program, established in 1988, has provided a cost effective method of gathering a large amount of information with which to track this fishery and associated populations. Results from angling diaries indicated increased angling effort, catch and success rates for muskellunge on Lake of the Woods since the early 1990s. Although the month of July accounted for the majority of angling effort and catch, angling success rates and sizes of fish reported in diaries improved monthly into the late fall. Angling success rates were consistently higher in angling diaries than from creel surveys, but both survey types showed similar long-term trends in the fishery. Angler diary data, incorporating both the numbers of fish caught and/or seen by anglers, were used to calculate catch equality indices which proved to be sensitive to changes in population abundance. Increased minimum length regulations for muskellunge during 1987-2001 have been largely responsible for a decline in harvest rates from an estimated 36% in 1986 to 0% since 1999. Although higher size limits have yet to produce more quality-sized fish in angler catches, diary survey data, supported by recent improvements in catch rates from assessment gill nets, would indicate that muskellunge recruitment has increased. This article concludes with a brief review of how muskellunge angler diary data has been used in the past, including recommendations to minimize biases associated with this survey method. [ABSTRACT FROM AUTHOR]

This paper consolidates and summarizes information on Ontario muskellunge, Esox masquinongy, sport fisheries derived from angler diary programs sponsored by the Ontario Ministry of Natural Resources (OMNR) and Muskies Canada Incorporated (MCI) from 1979 to 2004. Interest in muskellunge as a sport fish has increased substantially over the past 10-15 years. Muskellunge catches were found to be highly correlated with angling effort. Catch rates, expressed in terms of catch-per-unit-of-effort (CUE), have improved over the past decade to the point where, in 2001, the provincial CUE was 0.119. The long term catch rate is 0.069. This improvement in angling quality is attributed to new minimum size limit regulations and increased catch-and-release angling practices. Over the period from 1979-2004, release rates by muskellunge anglers have averaged 94%. Based on a sample size of 9,499 fish, the mean size of angled muskellunge over the past 26 years was 37.0 inches (94 cm). Numerous fish exceeding 50 inches (127 cm) are angled from Ontario waters each year. The incidence of lymphosarcoma, a highly contagious, malignant blood cancer, has averaged only 2% since 1979. Based on an analysis of this information, Ontario's muskellunge fisheries appear to be stable and sustainable. Volunteer angler diary programs provide an accurate and cost-effective means to monitor the status of muskellunge fisheries in Ontario. [ABSTRACT FROM AUTHOR]

The muskellunge was introduced in the Saint John River system from stockings in a headwater lake in the 1970s. They have migrated down the system as far as the river's first dam, Mactaquac Hydroelectric Facility, at Fredericton and appear to have established several reproducing populations along the river. This exotic invader represents a potential threat to the severely depleted Atlantic salmon stocks in the river. We radio-tracked muskellunge over a 2-year period in the middle reaches. Home ranges extended to ~100 km in both riverine and lacustrine areas, including 78% of individuals trans-located upstream of the dam making their way back through the dam successfully. Downstream of the dam, home ranges were <25 km. No spawning areas were detected. An isotope analyses of diet indicated that the large sub-adults and adults had established the greatest proportion of their biomass in a more 15N depleted environment typical of areas farther upstream. Isotope mixing models could not accurately determine the proportion of Atlantic salmon smolts that may have been consumed by muskellunge, but anadromous salmon had ≤7% probabilities of being in the diet. A bioenergetics model suggested ≤5% of the annual food intake by muskellunge occurs during the smolt out-migration period. For the Saint John River, the impacts of growing numbers of muskellunge are multi-faceted creating a complex management challenge. Muskellunge appear to minimally increase predation risk for Atlantic salmon smolts while their increasing numbers are creating a growing recreational fishery and potential threat to the native fish community and ecosystem. [ABSTRACT FROM AUTHOR]

Habitat utilization of native young-of-the-year (YOY) muskellunge, Esox masquinongy, was quantified by the type and density of vegetation present, water depth, and fish communities associated with their presence and abundance in nursery bays of the Upper St. Lawrence River. We completed 441 seine hauls and captured 400 YOY muskellunge in 11 bays that were sampled each July and August over a 3-year period (2002-2004). We hypothesized a change in habitat utilization related to increasing body size, as YOY muskellunge doubled in total length from July to August. Fine-leafed submerged and emergent macrophytes and prey availability (cyprinids, Notropis sp., banded killifish, Fundulus diaphanous and tessellated darter, Etheostoma olmstedi), were positively related to muskellunge use in July, while in August coverage of broad-leafed submerged macrophytes and increased overall vegetation density were the best habitat descriptor. In both months, muskellunge were associated with moderate (20-60%) vegetation coverage and density, however, captures were in areas of significantly greater vegetation coverage and density than was generally available. A negative relation of muskellunge occurrence with water depth, yellow perch, Perca flavescens, and stonewort, Chara vulgaris, was observed in both months. The negative relationship between muskellunge and depth, plus their strong linkages to nearshore submerged vegetation and forage fish that inhabit the nearshore areas, highlights the importance of protecting the ecological integrity of nearshore habitats. Our findings should assist managers in protecting native stocks, planning restoration and enhancement initiatives, and in regulating riparian and nearshore development. [ABSTRACT FROM AUTHOR]

Although muskellunge, Esox masquinongy, fisheries in northern US states and Canadian provinces are increasingly being managed by introduction of restrictive harvest regulations (e.g. 1370-mm (54′′) minimum length limits), many southern US muskellunge fisheries continue to be managed with comparatively liberal regulations (e.g. 762-mm (30′′) minimum length limits) that are implemented statewide. We studied the population dynamics of the New River, Virginia, muskellunge fishery and used predictive modeling to determine whether restrictive harvest regulations also might prove beneficial for this southern latitude fishery. A creel survey was also conducted to learn more about angler attitudes to the New River muskellunge fishery. Muskellunge grew quickly, with fish reaching harvestable lengths (762 mm, 30′′) in 2-3 years. Muskellunge fishing pressure, harvest rates, and voluntary release rates were low compared with reports for more northern areas. Most anglers, irrespective of how often they fished for muskellunge, defined "trophy" muskellunge to be approximately 1050-1100 mm (41-43′′) in length. Although angler support for restrictive harvest regulations was low, abundance of memorable-length (≥1070 mm, 42′′) muskellunge was predicted to increase under all evaluated length limits. Muskellunge yield would remain static at 914-mm (36′′) and 1016-mm (40′′) length limits, because of the rapid growth of fish, but yield would decline dramatically with a 1143-mm (45′′) length limit, because male muskellunge rarely exceeded 1100 mm (43′′). Because of rapid growth and low release rates, implementation of higher length limits (e.g. 965-1067 mm, 38-42′′) may indeed prove beneficial for augmenting "trophy" muskellunge production on the New River. Angler support for higher minimum length limits might be increased by educating anglers about the rapid growth rates of muskellunge and the expected size structure changes that will result from a length-limit increase. Size structure changes resulting from an increase in the minimum length limit may be difficult to detect because of potential increases in fishing pressure or reduced fish growth as a result of competition for food resources. Long-term monitoring of muskellunge growth and angling pressure may therefore be needed to ensure that new regulations are indeed benefitting the fishery. [ABSTRACT FROM AUTHOR]

Muskellunge, Esox masquinongy, were an important component of the Green Bay ecosystem prior to mid 1900s, but were extirpated by over-fishing, pollution, habitat degradation, and the introduction of exotic species. The Green Bay ecosystem improved after the passage of the Clean Water Act, and the Wisconsin Department of Natural Resources (WI DNR) started a muskellunge reintroduction program in 1989. Monitoring the results of reintroduction efforts is necessary to achieve the program goal of establishing a self-sustaining population. We used available data to provide a 2005 spawner abundance estimate for a Green Bay tributary, estimates of contributions to that spawning stock from fall fingerling and yearling stocking, a weight-length relationship, a growth analysis, and a description of size and age at maturity. Our results indicate that stocking efforts have been successful in producing an adult population, with yearlings contributing to the spawning stock at a higher proportion than fingerlings (14.69:1). Our weight-length and growth analyses suggest that Green Bay muskellunge are unlikely to reach record length, but that it is possible for females to achieve record weight. The rapid growth of Green Bay muskellunge results in their maturing at larger sizes than other stocks, but the relationship between age and maturity is not well understood. Reintroduction efforts in Green Bay have created stocked populations capable of supporting trophy fisheries, but evidence of successful natural reproduction has not been observed. Future research should focus on the reproductive requirements of muskellunge reintroduced into altered habitats. [ABSTRACT FROM AUTHOR]