A hitchhiker’s guide to the Maritimes: anthropogenic transport facilitates long‐distance dispersal of an invasive marine crab to Newfoundland

Aim To determine timing, source and vector for the recent introduction of the European green crab, Carcinus maenas (Linnaeus, 1758), to Newfoundland using multiple lines of evidence. Location Founding populations in Placentia Bay, Newfoundland, Canada and potential source populations in the north‐west Atlantic (NWA) and Europe. Methods We analysed mitochondrial and microsatellite genetic data from European and NWA populations sampled during 1999–2002 to determine probable source locations and vectors for the Placentia Bay introduction discovered in 2007. We also analysed Placentia Bay demographic data and shipping records to look for congruent patterns with genetic analyses. Results Demographic data and surveys suggested that C. maenas populations are established and were in Placentia Bay for several years (c. 2002) prior to discovery. Genetic data corroboratively suggested central/western Scotian Shelf populations (e.g., Halifax) as the likely source area for the anthropogenic introduction. These Scotian Shelf populations were within an admixture zone made up of genotypes from both the earlier (early 1800s) and later (late 1900s) introductions of the crab to the NWA from Europe. Placentia Bay also exhibited this mixed ancestry. Probable introduction vectors included vessel traffic and shipping, especially vessels carrying ballast water. Main conclusions Carcinus maenas overcame considerable natural barriers (i.e., coastal and ocean currents) via anthropogenic transport to become established and abundant in Newfoundland. Our study thus demonstrates how non‐native populations can be important secondary sources of introduction especially when aided by human transport. Inference of source populations was possible owing to the existence of an admixture zone in central/western Nova Scotia made up of southern and northern genotypes corresponding with the crab’s two historical introductions. Coastal vessel traffic was found to be a likely vector for the crab’s spread to Newfoundland. Our study demonstrates that there is considerable risk for continued introduction or reintroduction of C. maenas throughout the NWA.     

Phytoplankton and zooplankton as indicators of water quality in Discovery Bay,Jamaica

Several investigations exist which use planktonic communities as indicators of water quality in Jamaican and Caribbean Bays, however, few are conducted before there are obvious effects of eutrophication. Therefore, most of our ‘baseline’ data are for bays already severely affected by pollution. This study was conducted to assess water quality in Discovery Bay, Jamaica, before there were severe signs of eutrophication. The bay was monitored over a 12-month period (October 1995–September 1996) using 10 stations. Physicochemical data indicated a well mixed upper 5 m of water column, below which discontinuities in temperature/salinity profiles indicated the influence of colder, more saline waters associated with deep offshore currents. Physicochemical variables were within the range for oligotrophic systems with a tendency towards mesotrophic in localized areas close to the shoreline. Signs of anthropogenic stress were associated with the eastern, southwestern and western sections of the bay. Of the over 120 species of phytoplankton found in the waters of Discovery Bay, most were neritic/oceanic and diatoms dominated while 11 were found to be potentially harmful species. While these harmful species occurred at all stations they occurred most frequently at stations on the eastern side of the bay. About 107 zooplankton species were identified, 52 of which were copepods. The species also represented a mix of neritic and oceanic taxa and mean abundances for the area ranged from 1077 m⁻³ at the mouth of the bay to 3794 m⁻³ close to the south shore (station 6). Generally stations closest to shore had greater zooplankton abundances than centrally located bay stations and stations close to oceanic influence. Acartia tonsa and Lucifer faxoni showed greatest densities at shoreline areas of the bay while Oithona plumifera, Undinula vulgaris and Temora stylifera were important at stations closest to oceanic influences. These species were thus considered as indicators of these different areas within the bay. From physicochemical data and the planktonic assemblage, Discovery Bay cannot be considered polluted, it is still more accurately classified as generally pristine with mesotrophic zones in the eastern and southeastern sections of the bay. These data therefore provide a real baseline of conditions for similar tropical coastal embayments.     

Distributional patterns of humpback whales (Megaptera novaeangliae) along the Newfoundland East Coast reflect their main prey,capelin (Mallotus villosus)

On the Newfoundland foraging ground, humpback whales (Megaptera novaeangliae) primarily consume capelin (Mallotus villosus), which experienced a population collapse in the early 1990s, associated with altered timing of spawning and spawning migration. We examined whether humpback whale movement and distribution match these prey changes. Combining tour company whale sighting reports and photographs, citizen science reports of capelin spawning and scientific monitoring, whales were found to move northward along the east coast and whale aggregation presence within bays was associated with spawning capelin presence, being later in northerly bays. Whale aggregations arrived 8–20 days later than spawning capelin in northern bays, however, suggesting inconsistent tendencies to track high abundance spawning capelin aggregations during migration. Repeated scientific surveys during July–August 2009, 2010, 2012, 2014–2017, within a biological hotspot associated with capelin spawning sites in Notre Dame Bay, revealed that whale presence was influenced by the date of capelin spawning rather than capelin abundance metrics (i.e., biomass, number of shoals, shoal density, shoal area). A photo-identification catalog compiled during July–August, 2003–2017, revealed a 22% return rate of whales to the hotspot. Overall, findings suggest that capelin spawning sites are important foraging areas for humpback whales in coastal Newfoundland under these altered prey conditions.     

Diet and population size structure of the Arctic shanny,Stichaeus punctatus (Pisces: Stichaeidae), at sites in eastern Newfoundland and the eastern Arctic

Synopsis The size structure and diet of the Arctic shanny,Stichaeus punctatus, were studied at two sites, one at Nuvuk Islands in the Arctic, and one at Newman Sound, in eastern Newfoundland. The Newfoundland population showed peaks corresponding to 0+,1+, and an accumulation of older individuals, while the Nuvuk population was dominated by 2+ and 3+ combined, and individuals aged 6+ and older. Epiphytic, harpacticoid copepods were the most important food items for the smaller Arctic shanny, but the importance of harpacticoid copepods decreased with increasing fish size. Harpacticoid copepods are thus a link between the macro-algae and the young stages of the Arctic shanny. Since Arctic shanny are the main food used by black guillemots to feed chicks, these copepods are also an indirect link between benthic algal production and these seabirds.     

Mitochondrial DNA sequence variation and genetic stock structure of Atlantic cod (Gadus morhua) from bay and offshore locations on the Newfoundland continental shelf

Bay cod, Atlantic cod (Gadus morhua) that over-winter in the deep-water bays of northeastern Newfoundland, have historically been regarded as distinct in migration and spawning behaviour from offshore (Grand Bank) cod stocks. To investigate their genetic relationships, we determined the DNA sequence of a 307-base-pair portion of the mitochondrial cytochrome b gene for 236 adult cod taken from the waters off northeastern Newfoundland, including fish found over-wintering and spawning in Trinity Bay. Although 17 genotypes were found, a single common genotype occurs at a frequency of greater than 80% in all samples, and no alternative genotype occurs at a frequency of greater than 3%. Genotype proportions did not differ significantly among samples. Measures of genetic subdivision among sampling locations are nil. Cod over-wintering in Trinity Bay are not genetically distinct from offshore cod. In combination with tagging and physiological studies, these data suggest that there is sufficient movement of cod between bay and offshore locations to prevent the development or maintenance of independent inshore stocks. Adult cod that over-winter in Trinity Bay appear to represent an assemblage of temporarily nonmigratory fish that have become physiologically acclimated to cold-water inshore environments. The pattern of genetic variation in northern cod suggests a recent population structure characterized by extensive movement of contemporary individuals superimposed on an older structure characterized by a bottleneck in the population size of cod in the north-western Atlantic.     

The seasonal dynamics and distribution of burrowing shrimp larvae of the infraorders Gebiidea and Axiidea in Amursky and Ussuriysky Bays,the Sea of Japan

The species composition, period of occurrence, density, and distribution of the larvae of burrowing shrimp of the infraorders Gebiidea and Axiidea in Amursky and Ussuriysky bays (Sea of Japan) were studied in May–October 2008. Larvae of eight species of this group were found in plankton samples. The period of occurrence of larvae in the bays was longest in Upogebia major and Nihonotrypaea petalura (4 and 3 months, respectively). Zoeae of the rest of the species occurred in the plankton for no more than 2 months, indicating a single larval hatching during the reproductive season. The average density of gebiidean and axiidean larvae was low and reached the highest values (4 ind./m³) in June in Amursky Bay and in July in Ussuriysky Bay; their contribution to the total density of decapod larvae was not above 18%. In general, larvae of the family Upogebiidae dominated in Amursky Bay and larvae of the Callianassidae were predominant in Ussuriysky Bay. The zoeae of U. major (up to 37 ind./m³) and Nihonotrypaea makarovi (up to 46 ind./m³) were most numerous. Larvae of the family Axiidae were recorded only in very low numbers in both bays.     

Vertical distribution and ecological significance of chaetognaths in the Arctic environment of Baffin Bay

Summary The vertical distributions of species of chaetognaths are described to a depth of 1043 m in Baffin Bay during the summer. The dominant species in the southern region of the Bay were Eukrohnia hamata and Sagitta maxima and, in the northern region, E. hamata and S. elegans. The younger stages of all chaetognath species were found at depths above the older more mature stages. There was no evidence of any diurnal vertical migration by any species. The population structure of E. hamata was bimodal suggesting two sub-populations and a two year life cycle. Sagitta maxima showed a multimodal population suggesting a life cycle of four or more years. The population structure of E. elegans was unimodal. Gut contents showed that E. hamata fed at a higher rate than did S. maxima. E. hamata fed at a higher rate during the night but there was no significant difference between day/night feeding rates for S. maxima. It was estimated that E. hamata consumed up to 1.8 prey items day^-1 and S. maxima 0.5 prey items day^-1. The daily ration was influenced by the water temperature. Calculations showed chaetognaths are major predators on copepods consuming between 1.2 and 1.3% of the standing crop of copepods per day. Generally the maximum concentration of chaetognaths was found at a depth below the maximum concentration of copepods.     

The zooplankton community in bays of Toulon area (northwest Mediterranean Sea,France)

The abundance and the diversity of the zooplankton community were studied during an annual cycle in three shallow bays differently affected by anthropogenic inputs of Toulon area in the northwest Mediterranean Sea (France). Environmental variables of water quality were also considered. Our results discriminated Little Bay from the La Garonne and Niel Bay. Little Bay, heavely perturbed by anthropogenic inputs, had high chlorophyll a levels, abundant zooplankton, a low diversity index, a high dominance Index and a single dominant species (Oithona nana). La Garonne Bay and Niel Bay, much less polluted, had low chlorophyll a levels, low zooplankton abundance, low dominance Index and high diversity index and eveness. In addition, O. nana occurred rarely in the latter bays. Zooplankton successions were also different between Little Bay and the two other bays.     

Biology of the threespine stickleback,Gasterosteus aculeatus,and the blackspotted stickleback,G. wheatlandi,during their marine pelagic phase in the Bay of Fundy,Canada

Synopsis Two species ofGasterosteus were collected from the surface waters of 48 stations in the Bay of Fundy from 1979–1982. Densities varied widely according to locality and time of year (range: 1 fish 0.2 m^–2 to 1 fish 26.3 m^–2 of sea surface) but peaked within 30 km of the New Brunswick/Maine coast in July and August. A few adults were caught as far as 100 km from the coast in winter. Guts ofG. wheatlandi were significantly fuller (63.3 ± 0.6%) than those ofG. aculeatus (44.6 ± 0.1%) but there were no differences between male and female guts within species. Quantitatively, gut contents were very similar between species, consisting primarily of (99.4%): calanoid copepods (Centropages typicus Kroyer andEurytemora cfamericana Williams), copepod nauplii, cladocerans (Podon leuckarti Sars andP. polyphemoides Leuckart) and planktonic eggs (in decreasing order of importance).Gasterosteus wheatlandi ate significantly more calanoids thanG. aculeatus but all other prey types were eaten in similar amounts. Within species, there were no differences in the numbers of each prey type eaten over time. The most abundant calanoid species caught alongside the fishes in the sampling nets did not occur in the sticklebacks' diets; probably they were too large to be ingested.Gasterosteus aculeatus bred in inshore, brackish water ponds in late April. By late July most juveniles had migrated out into the Bay but a few remained until early September.Gasterosteus wheatlandi bred later in the brackish water ponds (late May) and juveniles began migrating into the Bay in early August; a few remained in the ponds until early September. Adults were found in the Bay alongside juveniles suggesting that individuals of both species may survive for a second year. In both species, growth rates of juveniles were greater in brackish water than in the sea.     

Demographic responses of arctic hares Lepus arcticus placed on two predominantly forested islands in Newfoundland

During January-April 1989. we monitored survival, reproduction, and body condition of 19 radio-collared arctic hares Lepus areticus introduced to two predominantly (80%) forested islands. Merchant (66 1 ha) and Burke (82 6 ha), in Placentia Bay, Newfoundland By late April, bone-marrow fat (42 7%) and kidney fat indices were lower than found in populations on the mountain barrens of western Newfoundland However, most island hares gained weight overwinter, and litter sizes (mean. 4 2 in utero) and testis weights (mean, 8 3 g) were as large or larger than recorded from other introduced and natural populations in Newfoundland The distribution of telemetry locations, tracks and feeding sites indicated that hares frequented the scattered barrens (totalling c 30 ha) on both islands in greater proportion than available These results suggest that, in the absence of snowshoe hares and mammalian predators, forested regions interspersed with small patches of barrens can sustain arctic hares     

Observations on the biology and seasonal variation in feeding of the east coast round herring Etrumeus wongratanai (Clupeiformes), off Scottburgh,KwaZulu-Natal,South Africa

The basic biology and ecology of the South African east coast round herring Etrumeus wongratanai was investigated from samples of fish collected between 2013 and 2016. This species is short-lived and reaches a maximum of 3 years of age, with rapid growth in its first year of life. It reproduces from June to December (austral summer) and condition factor was lowest in May through to August and increased from September, probably reflecting the physiological strain before and during spawning. Fish larvae were the most important food items consumed during summer, whereas eucalanid copepods were the most important prey at other times of the year. Stable-isotope data suggest that there are gradual changes in the trophic level with increasing fish size, δ¹⁵N and δ¹³C values also differed between seasons. The results obtained here are compared with those of other Etrumeus species, regionally and globally.     

Seasonal cycles of zooplankton from San Francisco Bay

The two estuarine systems composing San Francisco Bay have distinct zooplankton communities and seasonal population dynamics. In the South Bay, a shallow lagoon-type estuary, the copepods Acartia spp. and Oithona davisae dominate. As in estuaries along the northeast coast of the U.S., there is a seasonal succession involving the replacement of a cold-season Acartia species (A. clausi s.l.) by a warm-season species (A. californiensis), presumably resulting from the differential production and hatching of dormant eggs. Oithona davisae is most abundant during the fall. Copepods of northern San Francisco Bay, a partially-mixed estuary of the Sacramento-San Joaquin Rivers, organize into discrete populations according to salinity distribution: Sinocalanus doerrii (a recently introduced species) at the riverine boundary, Eurytemora affinis in the oligohaline mixing zone, Acartia spp. in polyhaline waters (18–30\%), and neritic species (e.g., Paracalanus parvus) at the seaward boundary. Sinocalanus doerrii and E. affinis are present year-round. Acartia clausi s.l. is present almost year-round in the northern reach, and A. californiensis occurs only briefly there in summer-fall. The difference in succession of Acartia species between the two regions of San Francisco Bay may reflect differences in the seasonal temperature cycle (the South Bay warms earlier), and the perennial transport of A. clausi s.l. into the northern reach from the seaward boundary by nontidal advection.Large numbers (>10⁶ m^–3) of net microzooplankton (>64 µm), in cluding the rotifer Synchaeta sp. and three species of tintinnid ciliates, occur in the South Bay and in the seaward northern reach where salinity exceeds about 5–10 Maximum densities of these microzooplankton are associated with high concentrations of chlorophyll. Meroplankton (of gastropods, bivalves, barnacles, and polychaetes) constitute a large fraction of zooplankton biomass in the South Bay during winter-spring and in the northern reach during summer-fall.Seasonal cycles of zooplankton abundance appear to be constant among years (1978–1981) and are similar in the deep (>10 m) channels and lateral shoals (<3 m). The seasonal zooplankton community dynamics are discussed in relation to: (1) river discharge which alters salinity distribution and residence time of plankton; (2) temperature which induces production and hatching of dormant copepod eggs; (3) coastal hydrography which brings neritic copepods of different zoogeographic affinities into the bay; and (4) seasonal cycles of phytoplankton.     

Identifying carbon sources and trophic position of coral reef fishes using diet and stable isotope (δ15N and δ13C) analyses in two contrasted bays in Moorea, French Polynesia

Stable isotope ratios (δ¹⁵N and δ¹³C) and diet of three fish species, Stegastes nigricans, Chaetodon citrinellus and Epinephelus merra, were analyzed on the fringing coral reefs of two bays that are differentially exposed to river runoff on Moorea Island, French Polynesia. S. nigricans and C. citrinellus relied mostly on turf algae and presented similar trophic levels and δ¹⁵N values, whereas E. merra fed on large invertebrates (crabs and shrimps) and had higher trophic levels and δ¹⁵N values. Discrepancies existed between stomach content and stable isotope analyses for the relative importance of food items. Bayesian mixing models indicated that sedimented organic matter was also an important additional food for S. nigricans and C. citrinellus, and fishes for E. merra. The main sources of organic matter involved in the food webs ending with these species were algal turfs and surface sediments, while water particulate organic matter was barely used. Significant spatial differences in C and N isotopic ratios for sources and fishes were found within and between bays. Lower ¹³C and higher ¹⁵N values were observed for various compartments of the studied trophic network at the end of each bay than at the entrance. Differences were observed between bays, with organic sources and consumers being, on average, slightly more ¹³C-depleted and ¹⁵N-enriched in Cook’s Bay than in Opunohu Bay, linked with a higher mean annual flow of the river at Cook’s Bay. Our results suggest that rivers bring continental material into these two bays, which is partly incorporated into the food webs of fringing coral reefs at least close to river mouths. Thus, continental inputs can influence the transfer of organic matter within coral reef food webs depending on the diet of organisms.     

Distribution of loliginid squids in a eutrophicated tropical coastal bay

Guanabara Bay is one of the most polluted bays in Brazil, although it supports some fisheries resources, among which are three species of loliginid squids: Lolliguncula brevis, Doryteuthis plei, and Doryteuthis sanpaulensis. This study aimed to assess the temporal and spatial variations of squids in the bay, relating their abundance variation to local environmental factors. We also aimed to characterize the population structure of squids, in order to establish their degree of occupancy in this estuarine system. Ten fortnightly hauls were carried out (two per area) from July 2005 to June 2007. Squids were identified, measured, weighed, sexed and classified according to maturity stage. The spatial distribution of the three species was not uniform; most individuals were found near the mouth of the bay. Abundances were significantly different among seasons due to the presence of SACW (South Atlantic Central Water) during the spring–summer season. Most of the populations of the three species consist of juveniles, and most adult Doryteuthis were also immature, which reinforces the role of Guanabara Bay as a nursery ground for loliginid squids. Concerning the degree of occupancy of squids in Guanabara Bay, L. brevis is considered an estuarine resident, D. plei uses the estuarine system as a nursery area for feeding and growth, and juveniles of D. sanpaulensis enter the bay with the flood tide to feed, generally following the SACW intrusion. This is the first study on squids in this estuarine system, which despite the high degree of environmental impact is shown to be an important area for the loliginid species.     

Feeding ecology of larval and juvenile black seabream (Acanthopagrus schlegeli) and Japanese seaperch (Lateolabrax japonicus) in Tolo Harbour, Hong Kong

Black seabream, Acanthopagrus schlegeli, and Japanese seaperch, Lateolabrax japonicus, are important commercial species in the coastal waters of western Pacific Ocean, including Japan, Korea and China. In Hong Kong, larvae and juveniles of these two species occur in bays and estuaries during late winter and spring. This study reports on the ontogenetic changes in food habits in larvae and juveniles of these species in an artificial rocky shore area. Copepods and cladocerans were the most numerous food items for black seabream. There was a shift to larger and benthic prey as the fishes grew. Japanese seaperch <2.1cm fed predominantly on copepods and cladocerans, while larger prey were added as fish size increased. Japanese seaperch >6.0cm were piscivorous. Maximum prey width increased with fish standard length and mouth gape width in both species. Overall, black seabream showed greater diet breadth than did Japanese seaperch. In black seabream, diet breadth increased with fish size. In Japanese seaperch, diet breadth increased with size for fishes <4.0cm, then decreased as the fishes became piscivorous. Prey selectivity in black seabream was determined using information on prey availability in plankton samples. In general, preference was stronger for cypris larvae, Penilia avirostris and decapod larvae than for copepods and podonids. In recent years, overfishing and environmental degradation have led to the decline of fish populations in Tolo Harbour. Absence of fishes with empty gut indicates that inner Tolo Harbour is still an important nursery area for these two commercial species.     

The benthic macro-algae of Georgian Bay,the North Channel and their drainage basin

Thirty-nine subgeneric taxa of macroalgae have been collected from 83 sites in Georgian Bay, the North Channel and their drainage basin. There were 15 species in the Bay and Channel and 32 species in streams, rivers and impoundments in the basin. Only 8 of the Bay and Channel species were also found in the watershed. Cladophora glomerata was the most important species in Georgian Bay and the North Channel, having an estimated 640 × 10³ m² cover and 19 × 10⁴ kg fresh weight standing crop. However, this species was largely concentrated on the southwestern shorelines of these water bodies. Its distribution along the northeastern shoreline appears to be limited by total ion and phosphorus levels. Chara globularis/vulgaris was the subdominant taxon in Georgian Bay and the North Channel with an estimated 70 × 10³ m² cover and 15 × 10³ kg fresh weight biomass. This species was more widely distributed than C. glomerata. No other taxon contributed significantly to the standing crop including the frequently occurring Ulothrix zonata, Zygnema spp. and Spirogyra spp. The maximum benthic macroalgal biomass was estimated to be approximately 10% of the phytoplankton biomass.     

Salinity effects on arm regeneration in Luidia clathrata (Echinodermata: Asteroidea)

The effect of salinity (20, 25, and 30?psu) on regeneration of two arms of adult starfish Luidia clathrata (n?=?8 per salinity treatment group collected from Pensacola Bay, Florida, USA 30° 20′ N, 87° 13′ W) was examined in a laboratory experiment (November 2009 to March 2010) to test the hypothesis that L. clathrata is adapted to euryhaline conditions found in bays with regards to arm regeneration. Regenerating arm condition (lengths and weights) relative to treatment was 20-psu treatment?<?25-psu treatment?<?30-psu treatment, and non-regenerating arm condition was 20-psu treatment?<?25-psu treatment?=?30-psu treatment. Luidia clathrata is not adapted to lower salinity conditions found in bays with regard to arm regeneration, despite the common occurrence of the species in bays. Lower salinity in bays should reduce the ability of L. clathrata to recover from damage sustained during, or just prior to, low-salinity periods.     

A comparative study of epiphytic algal communities on two common genera of sea-grasses in eastern Australia

Fifty-seven epiphytic species were found to occur on the two sea-grass hosts Zostera and Posidonia in Botany Bay and Jervis Bay, N.S.W. Among the algal epiphytes on Posidonia australis several indicator species were identified and it was found that their relative frequency of occurrence can be used to differentiate sites within the two bays. These indicator species can be used also to classify a collection from an unknown site within the region, and their relative occurrences may provide a useful index for early detection of changes in the bay environments.     

Zooplankton dynamics in a gypsum karst lake and interrelation with the abiotic environment

Zooplankton species composition and abundance variation was studied in Lake Amvrakia, which is a deep, temperate, gypsum karst lake situated in the western Greece. The two year survey of zooplankton revealed 33 species (23 rotifers, five cladocerans, four copepods and one mollusc larva). The mean integrated abundance of the total zooplankton ranged between 83.6 and 442.7 ind. L⁻¹, with the higher density to be recorded in the surface 0–20 m layer. Small numbers of specimens of almost all species were found also in the hypoxic or anoxic hypolimnion. Copepods and especially the calanoid Eudiaptomus drieschi dominated the zooplankton community throughout the sampling period, followed by Dreissena polymorpha larvae, rotifers and cladocerans. Seasonal succession among the cladocerans and the most abundant rotifer species was observed. The concentration of chlorophyll-a was the most important factor for the variation of total zooplankton, as well as for the rotifers’ community. Dissolved oxygen affected copepods and cladocerans, water level correlated mainly with the molluscs larvae of D. polymorpha, while temperature influenced the variation of several rotifers, the cladoceran Diaphanosoma orghidani and the mollusc larvae. Negative correlation of conductivity with the cladoceran Daphnia cucullata and the copepods E. drieschi and Macrocyclops albidus was found. The differences in species composition found in Lake Amvrakia in comparison to the nearby lakes are probably ought to the geographical isolation and perhaps to its particular chemistry (e.g., elevated conductivity).