Freshwater mollusks, crayfish and other invertebrates

Freshwater mollusks, crayfish and other invertebrates

Freshwater invertebrates are one of the most important groups of indicators of the health of rivers, lakes, and wetlands. Many of them live for decades, continuously filter water, participate in nutrient cycling, and form the basis of food webs.

A system is being created for long-lived speciesDREVO Freshwater Invertebrate Passport.

The starting age for individual certification is 16 years (for long-lived species).

1. Freshwater mollusks

Priority species

Why are shellfish especially important?

Each adult clam:

filters water;

reduces the amount of suspended matter;

reduces bacterial content;

participates in the nitrogen and phosphorus cycle;

creates habitats for microorganisms;

is a food source for fish, birds and mammals.

In addition, their shells allow us to study the history of the reservoir's condition over decades.

Passport classes

2. Freshwater crayfish

Priority species

Ecological role

Cancers:

recycle organic waste;

clean the bottom;

participate in the formation of benthic ecosystems;

are an important food for fish and birds;

serve as indicators of clean water.

Passport classes

3. Other long-lived invertebrates

For most freshwater invertebrates, individual age classification is impractical, as their lifespan typically ranges from a few months to several years.

However, it is possible to createpopulation passports or habitat passportsfor the following groups:

river sponges;

mshanki;

colonies of hydroids;

larvae of rare species of caddis flies;

rare species of dragonflies;

endangered freshwater snails.

DREVO Population Passport

For short-lived species the following are recorded:

number;

area of ​​distribution;

genetic diversity;

habitat quality;

population dynamics;

threats;

results of annual monitoring.

How River Rover Scout helps with passporting

Used:

high-resolution underwater cameras;

sonar;

side-scan sonar;

spectral analysis of the bottom;

mapping of mollusc colonies;

Crayfish recognition using DREVO AI.

Created:

map of mollusc colonies;

crayfish population map;

filtration zone map;

map of ecologically valuable bottom habitats.

The main principle

Long-lived mollusks and crayfish are the keepers of the river's memory.

In the systemDREVO Living Mountainsthey are considered not only as separate species, but also askey indicators of aquatic ecosystem healthTheir digital passports allow river conditions to be monitored for decades, and habitat maps become the basis for decision-making in river cleanup, riverbed restoration, and water resource management.

DREVO Freshwater Invertebrate Passport

Maximum table of freshwater mollusks, crayfish and other invertebrates

The basic principle of passportization

An individual digital passport is created for an individual if at least one condition is met:

confirmed or reasonably estimated age -16 years and older;

the species is rare, protected or locally endemic;

the individual has reproductive or genetic value;

The organism has been registered multiple times by River Rover Scout;

The individual serves as a long-term indicator of the state of the reservoir.

For short-lived and difficult to distinguish organisms, an individual one is not created, butpopulation passport or colony passport.

1. Freshwater bivalves

The European pearl mussel is the system's primary target. In Finnish populations, the maximum age recorded was approximately 54–254 years, while other studies report lifespans exceeding 100 years. In cold northern rivers, individual specimens can live extremely long lives.

2. Freshwater snails and gastropods

Most freshwater snails don't live past 16 years. For them, population certification is preferable.

When does a snail need an individual passport?

Only if:

the species is extremely rare;

the individual is contained in a scientific program;

its age has been documented since its appearance;

She belongs to a unique genetic line.

In a natural system, it is more important for snails to record:

number;

settlement area;

water quality;

state of the bottom substrate;

the presence of young age groups.

3. European freshwater crayfish

For the broad-clawed crayfish, scientific literature gives lifespan estimates of approximately 13–20 years, but ages around 20 years are considered rare and should not be determined by size alone.

4. Invasive cancers

The longevity of an invasive species should not automatically give it protected status.

Invasive American crayfish can carry the crayfish plague pathogen, which is deadly to many native European crayfish. Therefore, the primary goal is not to protect the individual, but to prevent its spread and contact with local populations.

5. World examples of long-lived freshwater crayfish

For global species, specific age thresholds must be established separately. The figures for one species cannot be generalized to the entire group of freshwater crayfish.

6. Other crustaceans

7. Freshwater sponges

Freshwater sponges are colonial organisms. It's difficult to determine the age of individual living parts, as the colony can partially die and then regenerate.

The colony passport includes

approximate area;

volume;

colony form;

substrate;

depth;

water quality;

state of symbiotic microorganisms;

seasonal recovery history;

signs of disease.

For sponges the criterion is16 years oldIt is not applicable without a long-term history of a specific colony. The primary object of protection is the stable colony and its habitat.

8. Freshwater bryozoans

Bryozoans form colonies and persist between seasons using stable dormant structures.

Colonies can exist in one area for many years, but individual zooids are usually short-lived. Therefore, they are assignedWOOD Colony ID, and not an individual age passport.

9. Freshwater hydras and colonial coelenterates

An age of 16 years for hydra is almost impossible to confirm in the wild, since individual identity during budding and regeneration is ambiguous.

10. Aquatic insects

Most adult aquatic insects have a short lifespan, but the larval stage of some species lasts for several years.

For insects, age records are almost unnecessary. It's much more valuable to record the following annually:

successful reproduction;

number of larvae;

emergence of adults;

availability of clean water;

condition of coastal vegetation.

11. Freshwater worms and leeches

12. Priority table for ages 16+

13. Age classes of mollusks

Age classes are adjusted for each species. The toothless mussel cannot be assessed by the same standards as the pearl mussel.

14. Age classes of crayfish

A separate scale is needed for long-lived Australian crayfish:

16–30 years old — passport individual;

31–50 years old – especially valuable;

more than 50 years - a living legacy of the reservoir.

15. What is recorded in the mollusk passport?

16. What is recorded in the cancer passport?

17. How River Rover Scout creates a map

For shellfish

Used:

underwater cameras;

laser scale frame;

high resolution sonar;

structured light at a short distance;

photogrammetry;

bottom substrate analysis;

Automatic shell recognition.

River Rover Scout creates:

map of the colonies;

density of individuals;

age structure;

juvenile zones;

areas of empty shells;

siltation boundaries;

risk zones from dredging.

For crayfish

Used:

night cameras;

soft lighting;

thermal methods only where they are physically applicable;

short-range sonar;

cameras at the burrows;

Automatic recognition of claws, shell and scars.

Created:

burrow map;

density map;

breeding zones;

wintering areas;

invasive species distribution boundary;

Sanitary map of the risk of crayfish plague.

18. River Rover Scout Restrictions

River Rover Scout can identify quite well:

coordinates;

species or group;

size;

colony density;

habitat condition;

reappearance of a large individual.

He can't reliably determine from the image alone:

the exact age of the mollusk;

exact age of cancer;

genetic line;

early stage infection;

reproductive success of the entire population.

To confirm you need:

safe manual inspection;

measuring the growth lines of the shell;

genetic analysis;

laboratory diagnostics;

re-monitoring;

specialized scientific methodology.

19. What not to do

The following is not allowed:

open live mollusks to determine age;

remove pearl mussels from the ground en masse;

publicly disclose the exact coordinates of rare colonies;

transfer mollusks between watersheds;

release farmed crayfish into natural rivers;

moving equipment between bodies of water without disinfection;

assigning a protected status to an invasive species due to its age;

clean the bottom before mapping the colonies;

consider an empty shell as evidence of a living population;

consider a large cancer to be automatically 16 years old.

20. DREVO Final Priority

Highest individual priority

European pearl oyster;

thick pearl barley;

pseudoanodonta;

large old toothless ones;

broad-clawed crayfish;

stone cancer;

rare endemic river mussels;

Long-lived Australian crayfish.

Priority of the population passport

other pearl barley and toothless;

freshwater snails;

cave crustaceans;

aquatic insects;

sponges;

mshanki;

hydras;

leeches;

zooplanktonic crustaceans.

The main principle

Not every invertebrate needs a name, but every long-lived individual, colony, and population should have a place on the map of the living river.

DREVO Freshwater Invertebrate Passportshould consist of three interconnected levels:

Individual Passport- for long-lived mollusks and rare old crayfish;

Colony Passport— for sponges, bryozoans, hydras and dense settlements;

Population Passport— for snails, insects, small crustaceans and other short-lived organisms.

This system will be able to preserve not only large, visible animals, but also the entire hidden foundation of the freshwater ecosystem.

DREVO Freshwater Vertebrate Passport