Salinity effects

American oysters have a normal salinity range of 10 to 30 ppt. Spawning American oysters can be found in areas of 10 to 30 ppt. Larvae are prevalent in regions from 7.5 to 22.5 ppt. Survival of Crassostrea virginica at <5 ppt is highly unlikely.

Although a minimum salinity of 10 psu is required for metamorphosis, these oysters thrive in ~13 psu waters, and are most abundant under these conditions.

Juvenile and adults both appear to prefer salinities of <15 ppt.

Larval rangia have a salinity tolerance of between 2-10 ppt, and require salinity for development. Adults will not tolerate salinities >18 ppt.

Bay anchovies are most abundant in regions of 0.5 - 25.0 ppt.

Preferred salinity was shown to be between 10-20 ppt.

Low salinity basin (5-7 psu). Physiological performance examined from 5-30 psu. Feeding & metabolic rates decreased with increasing salinity; nutritive absorption increased. Feces production and ammonia excretion rates decreased strongly from lowest to highest salinity. Greatest scope for growth at 7 psu.

An increase in salinity (up to 40 ppt) typically yields an increase in the mean number of benthic species and polychaete species.

In a laboratory experiment, specimens kept between 10-15 psu were much smaller than specimens kept at >25 psu. Smaller specimens kept at 10-15 psu were unable to reproduce.

Benthic macroinfaunal communities were shown to thrive with a higher biomass in brackish (12-16 ppt), rather than marine (22-27 ppt), areas of the same bay due to freshwater inflow. Changes in community structure typically occur between 18 and 22 ppt.

A field study was done in an estuary that normally has a low salinity <25 psu. When the salinity exceeded 25 psu, macrofaunal biomass appeared to decrease in density.

Benthic meiofaunal communities were observed to be most abundant where waters had salinity values of between 10 and 40 ppt. Greatest abundance was noted at 18 to 22 ppt.

Able to thrive in salinities <1 psu, Corbicula fluminea, Rangia cuneata, and Neritina usnea are good indicators of freshwater environments. Preferring mid to high range salinities (<10-15 psu), Tagelus plebeius, Crassostrea virginica, Mulinia lateralis, Littoraria irrorata, and Ischadium recurvum can be used to indicate that the environment is brackish or marine.

Littoridina sphinctosoma, Mediomastus californiensis and Rangia cuneata were observed to be quite euryhaline across the Lavaca Bay, as they were abundant at each sampling site despite salinity levels not being equivalent at all sampling stations. Sites ranged between 4 ppt and 24 ppt.

Benthic gastropods and bivalves a higher biomass in regions where salinity is at 8-16 ppt. Annelids were most abundant in regions of higher salinity of about 20-32 ppt. Measurements of biomass were taken from the San Antonio Bay.

It was observed that blue crabs were most abundant in salinities of between 18-23 ppt, although they were spotted in all regions of the salinity spectrum of a Texas estuary and are therefore presumed euryhaline.

Adults prefer salinities of <20 ppt. Juveniles prefer salinities of between 6-21 ppt.

Preferred salinity was shown to be between 0-15 ppt.

P. occidentalis prefer highly saline environments (>35 psu). They are most abundant in areas with higher salinities.

S. tiburo juveniles thrive in moderately saline conditions (30-35 psu); C. isodon thrive in (<20 psu) lower saline conditions, S. lewini prefer highly saline conditions (>35 psu). Sharks utilized in the study were juveniles.

Despite being apparently abundant in all regions of the salinity spectrum of a Texas estuary, brown shrimp seemed to be the most abundant in regions of >23 ppt.

Shrimp selected for salinities between 5-20 ppt. (Postlarval)

Adults prefer salinities of between 24-26 ppt. Juveniles prefer salinities of between 10-20 ppt.

Growth significantly higher at salinities of 8-12 ppt than at salinities of 2-4 ppt.

Preferred salinity was shown to be between 10-20 ppt.

In laboratory experiments with temperatures < 15 °C, postlarval survivial decreased in salinities < 5 ppt.

In laboratory experiments with temperatures 24.5-26.0 °C, postlarvae grew equally well in salinities of 2-40 ppt.

C. leucas thrives in 7-20 psu salinities and P. pectinata prefer higher salinities of 18-24 psu.

Bull sharks have the highest affinity for moderate salinities of about 10.5 psu.

Laboratory bioassays showed that H. limbata nymphs could survive elevated salinities (LC50 of 6.3 ppt at 18 °C, 2.4 ppt at 28 °C). Similar growth rates at 0,2,4, & 8 ppt.

In slightly brackish waters of 0.0-10.0 ppt, crabs C. maracaiboensis, C. bocourti, C. sapidus were most abundant. In brackish waters of 10.1-30.0 ppt, crabs C. exasperatus were most abundant. In near-marine waters of 30.1-33.0 ppt, C. marginatus, C. danac, and C. exasperatus were most abundant. In marine waters of 33.1-35.5 ppt, C. ornatus, C. marginatus and C. exasperatus were most abundant.

At constant salinity of 35 ppt, respiration rate increased with increased temperature. At constant temperature of 15 °C, respiration rate increased with increased salinity.

Upon the instigation of the smoltification stage, Chinook salmon prefer salinities of around 1.5 to 2.5 ppt.

Highly abundant in regions of >25.0 ppt.

Significant changes in salinity, either increasing from >1 ppt or decreasing from <16 ppt, are an environmental cue to induce spawning. Embryos and early larvae thrive in a strict salinity range between 2 and 15 ppt.

Highly abundant in areas of 0.5 - >25 ppt. Southern Florida and Texas estuaries have higher salinities than other Gulf of Mexico estuaries, so R. cuneata are less abundant in those areas.

Acartia tonsa was found in salinities >80 psu. Combined with previous information on this species, it can be concluded that the copepod has a higher salinity range compared to other fauna.

Can tolerate salinities between 13 and 30 ppt. They are considered primarily marine organisms.

When water inflow is decreased and, as a result, salinity is increased in the area, R. bonasusestablish themselves further upriver.

Despite being able to tolerate salinities between 0.0 and 18.0 psu, these fish thrive in 0.2 to 2.0 psu. Younger fish are found closer to the 0.2 range, and older fish are found closer to the 2.0 range.

Dermo are known to prefer waters of >15 ppt. Dermo cell division is known to increase at >10 ppt. Cell growth significantly drops with salinities <10 ppt.

Distribution is directly influenced by salinity. Although they can tolerate salinities as low as 12.4 psu, they much prefer higher salinities of about 30 psu. A high abundance of L. dirum will indicate that the area is highly saline.

Oyster growth is stunted at salinities <7.5 ppt; however, oysters can survive between 5-40 ppt. Salinities >25 ppt are not ideal and can yield greater mortalities for the community, as Perkinsus marinus thri

Bivalves Rangia cuneata, Rangia flexuosa and Macoma mitchelli are common indicators of low salinities (<10 ppt).

Gastropods Littoridina sphinctosoma and Probythinella protera are known to be indicative of river-influenced environments (<10 ppt).

In salinities of about 19 psu, diversity and biomass of estuarine macrobenthic communities tend to be significantly higher than in any other region of the estuary.

Immediately after heavy rainfall (~25 psu), spionid polychaetes showed large increases in density & richness versus normal values (~41 psu).

Species richness, abundance, and biomass decreased in the upstream direction, positively correlated with salinity. Highly significant spatial variation in macrofaunal communities along the salinity gradient. Salinity range: 0-40 ppt.

Chironomid larvae & polychaete Hobsonia florida: increased densities after freshwater inflow event (1-5 ppt). Mollusks Mulinia lateralis & Macoma mitchelli: increased densities & abundance during low flow event (~20 ppt). Streblospio benedicti & Mediomastus californiensis: positively correlated with increasing salinity in low flow.

Macrofauna increased abundances, biomass & diversity with increased inflow; decreased during hypersaline conditions. Macrofaunal biomass & diversity had nonlinear bell-shaped relationship with salinity: maximum biomass at ~19 ppt, maxiumum diversity at ~9 ppt. Meiofauna abundance increased with increasing inflow.

Increased density and biomass with increases in freshwater inflow and reduced salinities. Salinity ranged from 1-13 psu.

Infaunal community in low salinity regions (2-4 ppt) showed low species richness and abundance of bivalves, decapods, and Orbiniid polychaetes, but high abundance of amphipods and Nereid polychaetes compared to higher salinity regions (12-32 ppt).

Nematodes have the tendency to be most abundant in downstream areas of estuarine environments at all times of the year due to the salinity concentration closer to the marine areas being higher at >29 ppt. Estuarine productivity is presumed greater at lower to moderate salinities.

Tubificioides heterochaetus and Peloscolex gabriellae are indicative of environments with <10 ppt salinities.

Studies have shown that oysters are incapable of tolerating salinities <5 ppt for more than ~3 days. Exposure to >25 ppt waters will increase the risk of Perkinsus marinus and Thais haemostoma on oyster reefs. Salinities above 10 ppt typically induce spawning in estuarine oysters.

Adults prefer salinities of between 10-24 ppt. Juveniles prefer salinities of between 10-30 ppt.

Streblospio benedicti and Mediomastus ambista are common indicators of environments with salinities <10 ppt.

Estuarine shrimp and oyster populations are known to require salinities of 10-20 ppt to thrive in the environment. Between 1988-1990, shrimp and oyster populations in a Texas estuarine environment (Nueces Bay) dropped significantly due to a two-year drought. The drought raised salinities to >36 ppt.

Preferred salinity was shown to be between 20-25 ppt.

These crustaceans are typically only found in bays after a flood has occurred. They exist in salinities <5 ppt.

Highly abundant in areas of 0.0 - >25 ppt in the Matagorda Bay only. In other Texas bays, these shrimp have regions of high abundance in the 0.5 - 35 ppt. Associated with high abundance of vegetation or oysters.

Gray snapper are euryhaline, and have been observed in salinities between 0.0 ppt and 67.0 ppt.

Non-gravid, developing adults thrive in salinities of approximately 20-25 ppt. Postlarval and juvenile menhaden prefer salinities of anywhere between 5-30 ppt. However, a study was done in 2005 that concluded Gulf menhaden in the Sabine Estuary in Texas, USA preferred salinities between 3-6 ppt.

Gulf menhaden are most abundant in regions of <15 ppt and regions of 18-23 ppt.

Preferred salinity was shown to be between 0-12 ppt for both adults and juveniles.

Juveniles can be found in all salinity regions of the Matagorda Bay; however, in most other Texas bays they are most abundant in regions of 0.5 - >25 ppt

Preferred salinity was shown to be between 10-15 ppt.

After 2 hours, no mortality in salinities of 25-55 ppt. Almost all displayed dormant behavior < 20 ppt and > 55 ppt.

All species tested for response to salinities from 0-210 ppt. Tigriopus became dormant at 90 ppt died at 150 ppt. Tachidius became dormant at 60 ppt, died at 150 ppt. Tisbe died shortly after exposure to 45 ppt.

M. peninsulae is found in higher salinities of anywhere between 0.5 - >25 ppt, and M. beryllina are normally found in fresher waters of 0.0 - 0.5 ppt.

Insecta tend to be indicative of freshwater environments with salinities from 0.0 to 6.2 psu. Ampelisca abdita, Macoma mitchelli, Mulinia lateralis, Parandalia ocularis, and Streblospio benedicti are indicative of brackish environments with salinities from 15.0 to 26.2 psu. Apseudes sp. A, Corbula contracta, Periploma cf. orbiculare, Amphiodia atra, and Minuspio cirrifera are indicative of marine environments with salinities from 27.2 to 28.9.

Can tolerate salinities between 0 and 30 ppt. They are considered estuarine organisms.

This estuarine study had shown that C. errans are incapable of tolerating lower salinities of ~0.5 to 15 ppt. Abundance and salinity were positively correlated.

Sustained exposure (> 30 d) to salinity < 10 ppt significantly decreased survivorship.

These insects are known to be highly abundant in regions of low salinities, <5 ppt.

L. campechanus larvae thrive in lower salinities (30 psu); as they grow, they gradually move to more saline environments.

Upper stations (~20 ppt) and stations near high-flow tributaries (6-12 m3 s-1) were typified by decapod Eurypanopeus depressus & gobiid fishes. Downstream stations (~30 ppt) and stations near low-flow tributaries (0.2-2 m3 s-1) were typified by decapods E. depressus and Petrolisthes armatus. Community structure present at upper stations distinct from downstream; high-flow tributaries distinct from near low-flow tributaries.

During the wet season, C. amboinensis will alter their home range areas in an attempt to avoid freshwater inflow (decreased salinity). Juveniles were used in this study.

Adults and juveniles are abundant in regions of 0.5 - >25.0 ppt.

H. florida (other names including Hypaniola gunneri floridus and Amhicteis gunneri) are indicators of recent flooding events in the area. They are known to thrive in lower salinities than most polychaete worms, <5 ppt.

In the Trinity-San Jacinto Estuary, Mediomastus californiensis was found at high levels of abundance in every sampling site, regardless of salinity. They are known to be able to thrive in salinities of between 4 and 26 ppt.

Rangia cuneata were found to be indicative of areas consisting of <10 ppt. Paraprionospio pinnata were found in areas of 20 to ~33 ppt. The following moderately euryhaline species have been shown to favor anywhere between 5 to 30 ppt: Cossura delta, Glycinde solitaria, Littoridina sphinctosoma, Lyonsia hyalina floridana, Macoma mitchelli, Mediomastus californiensis, Mulinia lateralis, Nereis succinea, and Parandalia fauveli.

Diversity decreases significantly in benthic communities as a result of a major drop in salinity. Open water areas are more likely to be affected by salinity drops. Salinity drops in studied areas were from between 18-30 ppt to 5-18 ppt.

Significant declines of as little as 10 ppt in salinity can be lethal for most known sponges, even those adapted to tolerate estuarine conditions.

In a 25 year long study, red drum were most abundant in regions of <15 ppt and 15-18 ppt.

Juvenile red drum can be found in regions of >25 ppt.

In a laboratory experiment, the sharpnose shiner, smalleye shiner and plains minnow were shown to have high mortality curves at ~14 ppt, whereas the Red River pupfish and plains killifish were able to withstand salinities of up to ~31 ppt.

These fish were observed to have a salinity tolerance of up to 10 ppt.

Abundance, biomass, species richness, diversity & evenness significanty increased from salinity of ~6 ppt to salinity of ~25 ppt.

Most abundant in regions of >25 ppt salinity, although it is not uncommon to see them in 0.5 - 25.0 ppt salinity regions.

Abundant in regions of 0.5 - >25 ppt.

Can tolerate salinities between 4 and 26 ppt. They are considered estuarine organisms.

Organisms subjected to acute, repeated exposure to 25, 35, or 45 ppt. A. viridari hyperosmotic conformer at decreased salinity, but osmoconformer at increased saliniry. G. cylindrata always osmoconformer. T. parva always osmoconformer; decreased survival at 45 ppt.

Corbicula fluminea, Rangia cuneata, & Neritina usnea only species to occur < 1 psu. R. cuneata good indicator of mesohaline salinity zones with tolerence to 20 psu. Gastropod N. usnea common in fresh to brackish salinities. Polymesoda caroliniana present between 1-20 psu (oligo- to mesohaline zones). Tagelus plebius, Crassostrea virginica, Mulinia lateralis, Littoraria irrorata, & Ischadium recurvum good indicators for polyhaline salinity zones.

In areas of 0.5 to 25.0 ppt, adult and juvenile seatrout are abundant. In areas of greater than 25 ppt, adults can still be found in any season excluding Winter, and larvae can be found during the Fall.

Striped mullets are most abundant in regions of 15-18 ppt.

Mean salinity ranged from ~11-31 ppt. Standard deviation of salinity was best environmental correlate of mean plant biomass and benthic animal diversity. Less biota at stations with greater fluctuations in salinity. For every 3 ppt increase in standard deviation, total benthic plant biomass decreased by an order of magnitude.

Beginning at salinities of 7.0 ppt, Texas hornshells will become stressed and die shortly after.

Can tolerate salinities between 0.0 and 17.0 ppt. They are considered primarily freshwater organisms.

White shrimp have been spotted at all regions of Texas estuaries; however, they are significantly more abundant in regions of 18-23 ppt.

Adults prefer salinities of between 3-7 ppt. Juveniles prefer salinities of between 10-25 ppt.

Preferred salinity was shown to be between 10-15 ppt.