Maritime Habitats Research Articles

Tracing microplastic pollution in Mahi River estuary, Gulf of Khambhat, Gujarat, and their influence on functional traits of macrobenthos.

Most maritime habitats contain microplastic (MPs) contamination. The quality of the benthic ecosystem's habitat is declining as MPs accumulate in marine system. The contamination of MPs must therefore be investigated. We studied MPs pollution in the Mahi River, estuary, and macrobenthos. In the present study, the abundance of MPs fragments gradually decreased from the high tide zone to the low tide zone and muddy sediment has high MPsconcentrations due to sediment characteristics and particle size. The majority of sediment and biota MPs were fibrous and black. MPs in both silt and biota have identical chemical compositions (modified cellulose), shapes, and colors. A significant source of pollutants and MPs fluxing into the ocean is well within the river system. Perinereis aibuhitensis ingested the most MPs out of 11 species, whereas Amphipods did not show any presence of MPs. Our findings showed that functional characteristics are essential for macrobenthos MPs intake. MPs in macrobenthos are high due to biological functions such as feeding, ecological groups, feeding mechanisms, body size, and bioturbation. MPs in marine sediment and organisms aretracked down to the Mahi River exceeding 50km. The present work has investigated the idea that the macrobenthos that live in the sediment are ingesting the MPs that are building up there and this ingestion relies on the macrobenthos' functional characteristics.

Can the delayed effects of climatic oscillations have a greater influence on global fisheries compared to their immediate effects?

Climatic oscillations affect fish population dynamics, ecological processes, and fishing operations in maritime habitats. This study examined how climatic oscillations affect catch rates for striped, blue, and silver marlins in the Atlantic Ocean. These oscillations are regarded as the primary factor influencing the abundance and accessibility of specific resources utilized by fishers. Logbook data were obtained from Taiwanese large-scale fishing vessels for climatic oscillations during the period 2005-2016. The results indicated that the effect of the Subtropical Indian Ocean Dipole on marlin catch rates did not have a lag, whereas those of the North Atlantic Oscillation, Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation, and Indian Ocean Dipole had various lags. Pearson's correlation analysis was conducted to examine the correlations between atmospheric oscillation indices and marlin catch rates, and wavelet analysis was employed to describe the influences of the most relevant lags. The results indicated that annual atmospheric fluctuations and their lags affected the abundance and catchability of striped, blue, and silver marlins in the study region. This, in turn, may affect the presence of these species in the market and lead to fluctuations in their prices in accordance with supply and demand. Overall, understanding the effects of climatic oscillations on fish species are essential for policymakers and coastal communities seeking to manage marine resources, predict changes in marine ecosystems, and establish appropriate methods for controlling the effects of climate variability.

Monitoring temporal changes in coastal mangroves to understand the impacts of climate change: Red Sea, Egypt

This paper focuses on the current state of mangroves in Egypt, analyses how climate change is affecting mangrove forests and suggests a conservation strategy to safeguard this valuable maritime resource. Mangroves in Egypt are primarily found in regions around the Red Sea, making them popular for ecotourism across the globe. A crucial breeding and feeding ground for many commercial fishery species, mangroves are a maritime habitat that is both economically and environmentally significant and a variety of living things call them home. Mangroves are one of the most threatened tropical and subtropical ecoregions in the world. These threats come from both natural and human sources, including oil spills, human waste runoff, herbicide use, and coastal development, all of which have the potential to harm the environment. Mangrove habitats are immediately impacted by salinity changes and rising sea levels brought on by climate change. This is unfortunate as mangroves are one of the most important global carbon sinks, and their loss due to climate change may accelerate sea level rise and ocean acidification, which will cause the extinction of numerous commercial fish species. A conservation strategy should be implemented to safeguard the mangroves around the Egyptian Red Sea by using mitigation techniques, creating marine protected zones near the mangroves, and consulting the owners of the mangrove stalks. Analysis of multi-temporal satellite imagery is one of the most significant methods to assist decision-makers and environmental planners in obtaining high-precision information about environmental and climatic changes. Analysis of satellite imagery is a valuable way to detect, monitor, assess and map the environmental, human, and natural activities that are threatening the growth of the mangrove forest ecosystem. Change detection analyses using satellite imagery were conducted to evaluate the effects of rapid coastal sustainable development, including human urban and tourism activities; the decline and destruction of large areas of the mangrove forest for animal feeding along camel trade roads; and the threat of natural impacts such as flash flooding, coastal and soil erosion or human impacts such as established desalination plants and other human activities along the coastal zone of the Egyptian Red Sea.

MLDet: Towards efficient and accurate deep learning method for Marine Litter Detection

The relentless growth of plastic manufacturing since the 1980s has resulted in significant accumulation of litter throughout the ocean. Cleaning up this litter manually poses a major challenge, highlighting the value of autonomous underwater vehicles (AUVs) equipped with a robust vision detection algorithm. Despite prior studies, it remains challenging to employ AUVs to detect marine litter in actual maritime habitats. This paper introduces an efficient and accurate deep learning method called MLDet to cope with marine litter detection. The experimental findings show that the proposed method notably outperforms other object detectors. Furthermore, the present study comprehensively discusses the relationship between the proposed detection algorithm and recycling waste collected from marine litter. The encouraging conclusion of the study suggests that a dedicated detection algorithm is a reliable tool for automatically recognizing marine litter and sustaining a healthy ocean.

Overwintering and breeding patterns of monarch butterflies (Danaus plexippus) in coastal plain habitats of the southeastern USA

Understanding variability in species’ traits can inform our understanding of their ecology and aid in the development of management and conservation strategies. Monarch butterflies (Danaus plexippus) are native to the western hemisphere and are well-known for their long-distance migrations but have experienced significant population declines in recent decades. Here we use a 5-year capture-mark-recapture dataset to compare monarch distributions, mating activity, and larval host plant use between two coastal plain habitats in South Carolina, USA. We observed seasonally specific habitat use, with maritime habitats serving as overwintering areas while nearby inland swamps support significant breeding in spring, summer, and fall seasons due to an abundance of aquatic milkweed (Asclepias perennis). We also observed mating activity by fall migrating monarchs and their use of swallow-wort (Pattalias palustre) in the spring as an important larval host plant in maritime habitats. This phenology and habitat use of monarchs diverges from established paradigms and suggest that a distinct population segment of monarchs may exist, with significance for understanding the conservation status of monarch butterflies and associated habitats in eastern North America. Further research should explore how monarchs along the Atlantic coast of North America relate to other eastern monarch populations.

Proximal, mineral and bioactive attributes of two wild forage legumes of the maritime habitats of southwestern India

Proximal, mineral and bioactive attributes of two wild forage legumes of the maritime habitats of southwestern India

EVALUATION OF THE POTENTIAL HAZARDS OF SHIP-GENERATED WASTE IN MARITIME INDUSTRY USING A TYPE-2 FUZZY ANALYTICAL HIERARCHY PROCESS

Ships create a large amount of pollutions to marine and coastal environment where its pollutants have negative effects to human and maritime habitat. Depending on the nature of ship-generated waste, rules and regulations determine discharging procedures. This paper focuses on evaluating of potential hazards of ship-generated wastes on the environment whether it may be discharged into the sea or disposed of on port facilities. Thus, marine and costal environmental effects can be discussed analytically to improve human and ecological health. To achieve this purpose, analytic hierarchy process (AHP) extended with interval type-2 fuzzy sets (IT2FSs) is used. While AHP method is used for prioritizing the potential ship- generated waste, the IT2FSs deal with uncertainty and vagueness in the process of obtaining expert decision. Beside assessment of the environmental impacts, the paper contributes to enhance coastal and marine environmental awareness with respect to the ship-generated waste.

Evaluation of the Potential Hazards of Ship-Generated Waste in Maritime Industry Using a Type-2 Fuzzy Analytical Hierarchy Process

Ships create a large amount of pollutions to marine and coastal environment where its pollutants have negative effects to human and maritime habitat. Depending on the nature of ship-generated waste, rules and regulations determine discharging procedures. This paper focuses on evaluating of potential hazards of ship-generated wastes on the environment whether it may be discharged into the sea or disposed of on port facilities. Thus, marine and costal environmental effects can be discussed analytically to improve human and ecological health. To achieve this purpose, analytic hierarchy process (AHP) extended with interval type-2 fuzzy sets (IT2FSs) is used. While AHP method is used for prioritizing the potential ship-generated waste, the IT2FSs deal with uncertainty and vagueness in the process of obtaining expert decision. Beside assessment of the environmental impacts, the paper contributes to enhance coastal and marine environmental awareness with respect to the ship-generated waste.

The bee fauna of an Atlantic coastal plain tidal marsh community in Southern New England, USA

With growing evidence of changes in local abundance, geographical range, and species diversity of wild bees, it is imperative to document wild bee communities in representative habitats throughout North America. The Connecticut shoreline has historically been subject to many natural and anthropogenic disturbances, and there is a lack of baseline data regarding bee biodiversity in Connecticut’s maritime habitats. In this study, we characterize the wild bee fauna of a discrete maritime habitat in Connecticut, USA, and examine salt-marsh, beach dune, and coastal scrub bee communities adjacent to Long Island Sound. Patterns found are discussed in relation to recent coastal surveys in New England. Biweekly surveys were conducted at Grass Island (Guilford, CT) over a two-year period (2011-2012) using pan traps and effort-based (timed) net collecting from flowers. A total of 3928 individual bees were collected, representing five families, 18 genera and at least 80 species. Floral records for 374 individuals resulted in associations of 35 bee species with 19 species of flowers. Seventy percent of the bees captured in the net survey were visiting alien plants, with the exotic Rosa rugosa Thunb. having the highest level of bee diversity and relative abundance. The total number of bee species collected in this survey represents approximately 23% of the known Connecticut fauna, including four specialists associated with coastal and wetland habitats. The abundance and diversity of bees visiting alien plants on Grass Island, as well as the occurrence of these sand specialists, may prove to be of conservation concern as the Connecticut shoreline continues to be altered.

Seeking stakeholder consensus within Ireland's conflicted salmon aquaculture space

A 56-statement Q Methodology constructed a hierarchy of values from the views of eighty-six high-level, well-informed stakeholders on the subject of salmon aquaculture development in Ireland. These values, sorted by z-scores, provided a direct comparison on the strength of stakeholder priorities associated with salmon aquaculture, other maritime economic sectors, and the ecosystem goods and services they rely upon. By clustering issues within eight interrelated social-ecological systems themes and performing Principal Components Factor Analysis, five factor groups were identified. High-priority consensus views were identified from factor group Q sorts. Stakeholders broadly agree that maintaining healthy and productive maritime habitats is a priority for all related sectors, that the sector would benefit from an independent regulatory body, and that a policy movement away from single-sector and toward multi-sector approaches is needed to alleviate conflict in the shared maritime space. Ireland produced approximately 16,300 t of farmed salmon in 2016, one percent of the global share of production, and have are aiming to surpass 22,000 t per annum by 2023. This study shows that Q Methodology has the capacity to quantify hierarchies of values within communities and highlight areas of stakeholder consensus at a policy-relevant level. In doing so, Q Methodology allows policy-makers, managers, and stakeholder leaders to better define priorities, recommend broadly supported policies, and resolve conflict.

Intraspecific evolutionary relationships among peregrine falcons in western North American high latitudes.

Subspecies relationships within the peregrine falcon (Falco peregrinus) have been long debated because of the polytypic nature of melanin-based plumage characteristics used in subspecies designations and potential differentiation of local subpopulations due to philopatry. In North America, understanding the evolutionary relationships among subspecies may have been further complicated by the introduction of captive bred peregrines originating from non-native stock, as part of recovery efforts associated with mid 20th century population declines resulting from organochloride pollution. Alaska hosts all three nominal subspecies of North American peregrine falcons–F. p. tundrius, anatum, and pealei–for which distributions in Alaska are broadly associated with nesting locales within Arctic, boreal, and south coastal maritime habitats, respectively. Unlike elsewhere, populations of peregrine falcon in Alaska were not augmented by captive-bred birds during the late 20th century recovery efforts. Population genetic differentiation analyses of peregrine populations in Alaska, based on sequence data from the mitochondrial DNA control region and fragment data from microsatellite loci, failed to uncover genetic distinction between populations of peregrines occupying Arctic and boreal Alaskan locales. However, the maritime subspecies, pealei, was genetically differentiated from Arctic and boreal populations, and substructured into eastern and western populations. Levels of interpopulational gene flow between anatum and tundrius were generally higher than between pealei and either anatum or tundrius. Estimates based on both marker types revealed gene flow between augmented Canadian populations and unaugmented Alaskan populations. While we make no attempt at formal taxonomic revision, our data suggest that peregrine falcons occupying habitats in Alaska and the North Pacific coast of North America belong to two distinct regional groupings–a coastal grouping (pealei) and a boreal/Arctic grouping (currently anatum and tundrius)–each comprised of discrete populations that are variously intra-regionally connected.

O invazi masařky Liosarcophaga aegyptica (Salem, 1935) do střední Evropy a objevu masařky Heliophagella verstraeteni (Lehrer, 1975) na východním Slovensku (Diptera, Sarcophagidae)

The invasion of the subtropical flesh-fly Liosarcophaga aegyptica (Salem, 1935) into South Moravia was observed during late summer 2003. This African insect was known to occur in the maritime habitats of the Black Sea and after World War II sporadically also in eastern Hungary, southern Slovakia and Lower Austria. Its population density increased in the Danube Basin and the first flies were also captured in South Moravia during late summer 2003. Elementary analyses revealed that this flesh-fly prefers habitats with high species diversity and important species similarity and that it might become sedentary in this territory. The flesh-fly Helicophagella verstraeteni (Lehrer, 1975) accompanying very dry and warm habitats of Romania, Hungary and France was discovered in a similar habitat of eastern Slovakia and is new to the fauna of Central Europe. Results of single linkage analyses in communities with Liosarcophaga aegyptica are presented together with the figures of the male genitalia of the two species of flesh-flies treated.

The Importance of Agricultural Landscapes as Key Nesting Habitats for the American Black Duck in Maritime Canada

Given historical patterns of decline, the American Black Duck (Anas rubripes) has long been a species of concern. To support the identification of core Maritime habitat, the distribution of breeding ducks was mapped at the landscape scale through the combination of GIS-based land cover information and five years of intensive aerial surveys (2006–2010). A predictive, mixed effects model was used to generate the maps, based on the weighted average of coefficients for the top 95% of all-possible models (as measured by AIC weights). The results of the averaged mixed model indicated that annual variation (YEAR), availability of surface water (WET_AREA, LAKE_AREA and WET_DIVERSITY) and occurrence of active agricultural landscapes (AG_PROP and ROAD_DENSITY) were strongly associated with the number of breeding pairs. The presence of larger numbers of breeding ducks in agricultural landscapes represents a departure from studies conducted in more intensively utilized regions (e.g. southern Ontario and Quebec), and suggest that the benefits of breeding in Maritime agricultural areas outweigh potential costs. Using 34,659 prediction points, duck distribution was modeled in relatively high and low years (2008 and 2006, respectively), resulting in detailed maps suitable for the identification of priority areas for habitat restoration and enhancement. In order to help refine conservation management plans, future work should more closely examine the impact of different types and combinations of Maritime agricultural production to better understand the way these landscapes attract breeding ducks.

Influence of summer marine fog and low cloud stratus on water relations of evergreen woody shrubs (Arctostaphylos: Ericaceae) in the chaparral of central California

Mediterranean-type climate (MTC) regions around the world are notable for cool, wet winters and hot, dry summers. A dominant vegetation type in all five MTC regions is evergreen, sclerophyllous shrubland, called chaparral in California. The extreme summer dry season in California is moderated by a persistent low-elevation layer of marine fog and cloud cover along the margin of the Pacific coast. We tested whether late dry season water potentials (Ψ(min)) of chaparral shrubs, such as Arctostaphylos species in central California, are influenced by this coast-to-interior climate gradient. Lowland coastal (maritime) shrubs were found to have significantly less negative Ψ(min) than upland interior shrubs (interior), and stable isotope (δ(13)C) values exhibited greater water use efficiency in the interior. Post-fire resprouter shrubs (resprouters) had significantly less negative Ψ(min) than co-occurring obligate seeder shrubs (seeders) in interior and transitional chaparral, possibly because resprouters have deeper root systems with better access to subsurface water than shallow-rooted seeders. Unexpectedly, maritime resprouters and seeders did not differ significantly in their Ψ(min), possibly reflecting more favorable water availability for shrubs influenced by the summer marine layer. Microclimate and soil data also suggest that maritime habitats have more favorable water availability than the interior. While maritime seeders constitute the majority of local Arctostaphylos endemics, they exhibited significantly greater vulnerability to xylem cavitation than interior seeders. Because rare seeders in maritime chaparral are more vulnerable to xylem cavitation than interior seeders, the potential breakdown of the summer marine layer along the coast is of potential conservation concern.

Variations physiologiques dans des populations de thuyas géants (Thuja plicata Donn ex D. Don) en réponse à une sécheresse courte

• Variation in the ability of western redcedar ( Thuja plicata Donn ex D. Don) populations to withstand water stress may exist because this species is found in coastal and interior biogeoclimatic subzones representing the full range of precipitation regimes in British Columbia, Canada.• Seven western redcedar populations from locations in British Columbia, representing a wide range of habitat types, were assessed for their gas exchange and water relations response to controlled drought. • Before drought, population variation occurred in stomatal conductance, net CO 2 assimilation rate and intrinsic water use efficiency and the relative water content at turgor loss point. During drought, populations had different responses of net CO 2 assimilation to decreasing predawn shoot water potential. After drought, populations differed in stomatal conductance and intrinsic water use efficiency, plus osmotic potential at turgor loss point, osmotic potential at saturation and apparent cuticular transpiration. Western redcedar populations from drier-inland habitats had a lower osmotic potential at turgor loss point, lower relative water content at turgor loss point and lower apparent cuticular transpiration in response to drought than populations from coastal origin with temperate maritime habitat.• Reduction of cuticular water loss and adjustments of cellular water relations in response to drought was found to occur among seven western redcedar populations originating along a precipitation gradient while; there were minimal population differences in the gas exchange response to drought.

Review: Depth, navigation and orientation in crabs: Angular acceleration, gravity and hydrostatic pressure sensing during path integration*

This review shows how well the published work on the neural basis of balance and hydrostatic pressure reception in crabs agrees with the analyses and models of path integration. Fiddler crabs allow analyses at the level of behaviour. With considerable accuracy, they continuously show the direction to home with their body orientation and use idiothetic path integration to calculate a home vector from the internal measurements of their locomotion. All crabs have a well-developed vestibular system in the statocyst with horizontal and vertical canals which is used for angular acceleration sensing and depth reception. Large identified interneurones abstract the component of angular acceleration in one of the three orthogonal planes. These have properties consistent with a key role in path integration, combining vestibular and proprioceptor information with a central excitatory drive from the hemiellipsoid bodies. They have been monitored during walking, swimming and even in freefall for a 22 s period in parabolic flight. * Note: This review is part of the collection of reviews on Animal Orientation and Navigation in Marine, Maritime and Freshwater Habitats published in Volume 39(1) of the journal.

Scuttle flies (Diptera: Phoridae) of saline habitats of the Gulf of Gdańsk, Poland

Results ofa survey ofthe scuttle flies (Diptera: Phoridae) of saline habitats ofthe Gulf of Gdańsk are reported. Within three study seasons (1999—2001), at ten 10 localities representing coastal brackish and maritime habitats, 39 phorid species were collected. Among these, 36 were new to these areas, and Xenotriphleba dentistylata Buck was the first record for Poland. The dominance structure, phenology and abundance ofphorids of saline habitats are described.

Louis Vuitton Cup

En At the beginning of October 2005 in (Western Sicily) the Louis Vuitton cup preliminaries will take place. This event, giving an important chance to develop the whole area, conflicts with another point of view: the one (i.e. Louis Vuitton cup preliminary regattas), for a territorial restyling and land development without any respect of EU and national laws. In contrast the other one tries to protect cultural, landscape and the natural wellbeing of the whole area; thoroughly respecting the law and it's legalities as well as environmental protection principles. Indeed, the land development for the Louis Vuitton cup, insists that the natural reserve Trapani and Paceco's Salt saltworks system, is becoming an obstacle for developing the coastal area. Works are leading to the reduction of some Posidonia beds, the Calendula maritime habitat, (which is an important endemic species in the Reserve) and in general, modification of the extension of many habitat patches which represent an important ecological corridor for the transient avifauna to and from Africa. Environmental organizations and National Guard actions against the development have concurred. Up until now, the negative actions against the environment and the saltworks systems are in control. This precedent is destined to continue also after the sports event. It Sara (Sicilia occidentale) il teatro dei preliminari della Louis Vuitton cup che si svolgera all’inizio dell’ottobre 2005. Tale evento, pur offrendo un’importante occasione En At the beginning of October 2005 in (Western Sicily) the Louis Vuitton cup preliminaries will take place. This event, giving an important chance to develop the whole area, conflicts with another point of view: the one (i.e. Louis Vuitton cup preliminary regattas), for a territorial restyling and land development without any respect of EU and national laws. In contrast ... Sq Ne fillim te Tetorit 2005 do te zhvillohen ne (Siciline Perendimore) eleminatoret e kupes Louis Vuiton . Aktiviteti, qe eshte nje shans i madh per zhvillimin e gjithe zones Ro La inceputul lunii octombrie 2005 vor avea loc in (vestul Siciliei) preliminariile cupei Louis Vuitton. Chiar daca acest eveniment, respectiv preliminariile cupei pentru regata El Στην αρχή τον Οκτωβρίου του 2005 στο Τrapani (δυτική Σικeλία) θα πραγματοποιηθούν τα προκαταρκτικά του κυπέλλου Louis Vuitton. Αυτό το γeγονός, δίνοντας μια σημαντικής eυκαιρία να αναπτυχθeί ολόκληρη η πeριοχή, συγκρούeται μe μια άλλη άποψη: Η πρώτη άποψη, τα Προκαταρκτικά κυπέλλου ιστιοπλοΐας του Louis Vuitton, αποβλέπeι σe eδαφικές αναδομήσeις και στην βeλτίωση Bg В началото на Октомври 2005 в Трапани (Западна Сицилия) ще се проведе предварителният кръг на регатата Louis Vuitton. Това събитие, което е от значение за развитието на цялата област, противоречи на друга концепция: шампионата Louis Vuitton подкрепя идеята за преструктуриране в териториалното развитие без да се съобразява с европейското и национално законодателство, докато алтернативната концепция

Comparative water relations of sub-Antarctic and continental Antarctic oribatid mites

Water availability, in addition to cold, is important in limiting biotic distribution in the Antarctic regions. In general, inland continental Antarctic habitats are dry, relative to maritime and sub-Antarctic habitats. This investigation compares the water relations of an endemic continental Antarctic oribatid mite, Maudheimia petronia Wallwork, and two sub-Antarctic oribatid mites, Halozetes fulvus Engelbrecht and Podacarus auberti Grandjean. M. petronia showed enhanced survival of dehydrating conditions, which may be attributable to both its greater resistance to and tolerance of water loss. The estimated lethal exposure times (LT50) for M. petronia, P. auberti and H. fulvus held at 15°C and 0–5% RH were 250, 135 and 51 h, respectively. M. petronia lost water significantly more slowly than the sub-Antarctic mites (P 0.05). The mean losses of initial body water content after 45 h were 18.9, 27.3 and 29.3% for M. petronia, P. auberti and H. fulvus, respectively, and lethal water losses causing 50% of the sample to die were 65, 52, and 28%, respectively. These data suggest physiological adaptation by M. petronia for existence in periodically dry “chalikosystem” habitats at Antarctic nunataks. Comparisons of tolerance of submersion in freshwater showed P. auberti to be superior to M. petronia; the LT50 values for submersion were >146 h and 32 h, respectively. Tolerance of submersion by P. auberti may be important for its existence in wet sub-Antarctic habitats. Conversely, the poor tolerance shown by M. petronia suggests that this mite has not been associated with moist environments.

Allozyme Divergence and the Mode of Speciation for Coreopsis gigantea and C. maritima (Compositae)

Coreopsis gigantea and C. maritima consist of herbaceous perennial, diploid plants oc- cupying maritime habitats in California and Baja California. They are distinct from all other members of Coreopsis and comprise the only two members of section Tuckermannia. The two species differ by a number of morphological features but their synthetic hybrids are highly fertile, and their allopatric distributions appear to be largely responsible for lack of hybridization under natural conditions. An electrophoretic study of 10 enzymes revealed a lowered mean genetic identity for populations of the two species as compared to conspecific populations. The lowered identity ostensibly results in part from mutations that have accumulated at isozyme genes during the gradual divergence of the two taxa via a geographic mode of speciation. This pattern is contrasted with that found in a number of annual plants where presumed rapid speciation is accompanied by little or no divergence at genes specifying soluble enzymes. Greater gene diversity was found in C. maritima than in C. gigantea, and this suggests possible alternatives within the geographic mode of divergence. Apparent gene duplications for several enzymes are reported and discussed briefly.